RNA polymerase IV complex

RNA polymerase IV is a multisubunit RNA polymerase complex found in the nucleus of plants and involved in accumulation of siRNAs and in DNA methylation-dependent silencing of endogenous repeated sequences. Pol IV is composed of subunits that are paralogous or identical to the 12 subunits of Pol II. The largest and second-largest subunits of Pol IV are the catalytic subunits and share similarity with the corresponding subunits of other eukaryotic and bacterial multisubunit RNA polymerases. The second largest subunit is also found in RNA polymerase V, while the largest subunit is found only in RNAP IV complex.


plastid-encoded plastid RNA polymerase complex

biolink:CellularComponent biolink:AnatomicalEntity biolink:OrganismalEntity biolink:BiologicalEntity biolink:NamedThing biolink:PhysicalEssence biolink:SubjectOfInvestigation biolink:ThingWithTaxon biolink:PhysicalEssenceOrOccurrent

An RNA polymerase complex containing polypeptides encoded by the plastid genome. Plastid-encoded DNA-directed RNA polymerases resemble eubacterial multisubunit RNA polymerases, with a core composed of alpha, beta, and beta-prime subunits. Some forms contain multiple additional subunits. An additional sigma factor subunit is required for promoter recognition.


plastid-encoded plastid RNA polymerase complex A

A plastid-encoded DNA-directed RNA polymerase complex that resembles eubacterial multisubunit RNA polymerases, with a core composed of alpha, beta, and beta-prime subunits. An additional subunit, a sigma factor, is required for promoter recognition. PEP-A is generated from the PEP-B form during chloroplast maturation to generate a complex composed of at least thirteen polypeptides that is not sensitive to the antibiotic rifampicin, like its precursor form the PEP-B complex.


Tic complex

The translocon of the inner envelope of chloroplasts, which facilitates the import of proteins across the chloroplast inner membrane.


signal recognition particle, endoplasmic reticulum targeting

A ribonucleoprotein particle of 325 kDa composed of a 7S (300 nucleotide) RNA molecule and a complex of six different polypeptides. This binds both to the N-terminal signal peptide for proteins destined for the endoplasmic reticulum as they emerge from the large ribosomal subunit and also to the ribosome. This binding arrests further translation thereby preventing the proteins from being released into the cytosol. The SRP-ribosome complex then diffuses to the endoplasmic reticulum where it is bound to the signal recognition particle receptor, which allows resumption of protein synthesis and facilitates the passage of the growing polypeptide chain through the translocon. Through a process involving GTP hydrolysis, the SRP-SRP receptor complex dissociates and SRP returns to the cytosol. Of the six polypeptides of SRP the 54 kDa subunit (SRP54) is the central player. It contains an N-terminal GTPase domain and a C-terminal domain that binds directly to the signal peptide and the SRP RNA. Examples of this component are found in Mus musculus, Saccharomyces cerevisiae and Arabidopsis thaliana.


equatorial microtubule organizing center

A microtubule organizing center formed by a band of gamma-tubulin that is recruited to a circumferential band of F-actin at the midpoint of a cell and which nucleates microtubules from the cell division site at the end of mitosis.


left nucleus

One of the two nuclei found in Giardia species (trophozoite stage). It is located on the left side of the cell when viewed from the dorsal side.


telopode

A telopode is a plasma membrane bounded cell projection that is present on a telocyte and is tens to hundreds of microns long. Telopodes form a labyrinthine system communicating through gap junctions.


FNIP-folliculin RagC/D GAP

A heterodimeric complex that functions as a GTPase-Activating Protein (GAP) Complex for members of the Rag family of GTPases. In the budding yeast, this complex contains Lst4 and Lst7, while the orthologous mammalian complex contains follicular (FLCN) and either follicular interacting protein 1 (FNIP1) or FNIP2.


GTPase activator complex

A protein complex which is capable of GTPase activator activity.


Bfa1-Bub2 complex

A protein complex that acts as a two-component GTPase-activating protein for Tem1 GTPase, thus regulating a signal transduction cascade, called the mitotic exit network (MEN), which is required for mitotic exit and cytokinesis. Bub2/Bfa1 keeps Tem1 inactive until the spindle is properly oriented, thus inhibiting MEN activation.


A axonemal microtubule

A complete microtubule with 13 protofilaments that fuses with an incomplete microtubule called B tubule (containing 10 protofilaments only) to form an axonemal outer doublet. Inner and outer dynein arms, as well as the radial spoke, are attached to the A tubule.


lamin filament

Any of a group of intermediate-filament proteins that form the fibrous matrix on the inner surface of the nuclear envelope. They are classified as lamins A, B and C.


skeletal muscle myofibril

A myofibril of a skeletal muscle fiber.


dendritic microtubule

Any microtubule in a dendrite, a neuron projection.


type III intermediate filament

A type of intermediate filament, typically made up of one or more of the proteins vimentin, desmin, glial fibrillary acidic protein (GFAP), and peripherin. Unlike the keratins, the type III proteins can form both homo- and heteropolymeric IF filaments.


fibronectin fibril

A supramolecular fiber formed from fibronectin molecules. The fibrils are 5 to 25nm in diameter and can form branched meshworks.


intraconoid microtubule

A microtubule located such that it threads through the conoid and projects through the polar ring.


collagen network

A supramolecular complex that consists of collagen triple helices associated to form a network.


astral microtubule

Any of the spindle microtubules that radiate in all directions from the spindle poles and are thought to contribute to the forces that separate the poles and position them in relation to the rest of the cell.


kinetochore microtubule

Any of the spindle microtubules that attach to the kinetochores of chromosomes by their plus ends, and maneuver the chromosomes during mitotic or meiotic chromosome segregation.


post-anaphase array microtubule

Any microtubule that is part of a post-anaphase microtubule array.


mitotic spindle polar microtubule

Any of the mitotic spindle microtubules that come from each pole and overlap at the spindle midzone.


smooth muscle contractile fiber

The contractile fiber of smooth muscle cells.


meiotic spindle astral microtubule

Any of the meiotic spindle microtubules that radiate in all directions from the spindle poles and are thought to contribute to the forces that separate the poles and position them in relation to the rest of the cell.


actomyosin contractile ring actin filament

Any actin filament that is part of a actomyosin contractile ring.


polar microtubule

Any of the spindle microtubules that come from each pole and overlap at the spindle midzone. This interdigitating structure consisting of antiparallel microtubules is responsible for pushing the poles of the spindle apart.


collagen sheet

A protein complex that consists of collagen triple helices associated to form a sheet-like network.


subpellicular microtubule

Singlet microtubule that lie underneath the inner membrane pellicle complex and emanate from the basal ring of the conoid.


microfibril

Extracellular matrix components occurring independently or along with elastin. Thought to have force-bearing functions in tendon. In addition to fibrillins, microfibrils may contain other associated proteins.


cortical microtubule

Arrays of microtubules underlying and connected to the plasma membrane in the cortical cytosol.


cardiac myofibril

A cardiac myofibril is a myofibril specific to cardiac muscle cells.


actin filament of cell cortex of cell tip

Any actin filament that is part of a cell cortex of cell tip.


complex of collagen trimers

A complex of collagen trimers such as a fibril or collagen network.


paraflagellar rod

A large lattice-like axial structure found in some flagellated protists which extends alongside the axoneme. Protein components of the paraflagellar rod are likely implicated, among other, in adenine nucleotide signaling and metabolism, and in calcium signaling.


mastigoneme

A hair-like structure covering the flagella found in some algae (heterokonts and cryptophytes). It is approximately 15 nm in diameter, and usually consist of a tubular shaft that itself terminates in smaller hairs. It is composed of glycoproteins and, likely, carbohydrates. Mastigonemes may assist in locomotion by increasing the surface area of a flagellum.


C2 axonemal microtubule

One of two microtubules present in the axonemal central pair. It is distinguishable from the C1 axonemal microtubule (also called C1 tubule) by the presence of differing protein components of the projections.


collagen beaded filament

A supramolecular assembly of collagen trimers with a 'beads on a string'-like structure.


outer dense fiber

A supramolecular fiber found in the flagella of mammalian sperm that surrounds the nine microtubule doublets. These dense fibers are stiff and noncontractile. In human, they consist of about 10 major and at least 15 minor proteins, where all major proteins are ODF1, ODF2 or ODF2-related proteins.


horsetail-astral microtubule array

An array of astral microtubules that emanates from the spindle pole body during meiosis and facilitates horsetail nuclear movement.


intranuclear rod

A macromolecular fiber consisting of actin and cofilin that is formed in the nucleus as a consequence of chemical or mechanical stress conditions.


mitotic spindle microtubule

Any microtubule that is part of a mitotic spindle; anchored at one spindle pole.


mitotic spindle astral microtubule

Any of the mitotic spindle microtubules that radiate in all directions from the spindle poles and are thought to contribute to the forces that separate the poles and position them in relation to the rest of the cell.


banded collagen fibril

A supramolecular assembly of fibrillar collagen complexes in the form of a long fiber (fibril) with transverse striations (bands).


aster

An array of microtubules emanating from a spindle pole MTOC that do not connect to kinetochores.


neurofilament

A type of intermediate filament found in the core of neuronal axons. Neurofilaments are heteropolymers composed of three type IV polypeptides: NF-L, NF-M, and NF-H (for low, middle, and high molecular weight). Neurofilaments are responsible for the radial growth of an axon and determine axonal diameter.


myosin filament

A supramolecular fiber containing myosin heavy chains, plus associated light chains and other proteins, in which the myosin heavy chains are arranged into a filament.


glial filament

An intermediate filament composed of glial fibrillary acidic protein (GFAP) and found in astrocytes.


mitotic spindle kinetochore microtubule

Any of the mitotic spindle microtubules that attach to the kinetochores of chromosomes by their plus ends, and maneuver the chromosomes during mitotic chromosome segregation.


striated muscle myosin thick filament

Bipolar filaments formed of polymers of a muscle-specific myosin II isoform, found in the middle of sarcomeres in myofibrils.


cytoophidium

A subcellular filamentary structure where CTP synthase is compartmentalized in a range of organisms including bacteria, yeast, fruit fly, rat and human.


B axonemal microtubule

An incomplete microtubule containing 10 protofilaments that fuses with a complete microtubule called A tubule (containing 13 protofilaments) to form an axonemal outer doublet.


cortical microtubule, transverse to long axis

Arrays of microtubules underlying and connected to the plasma membrane, in the cortical cytosol, oriented mainly with their axes transverse to the long axis of the cell (and root in plants). In plants it influences the direction of cellulose microfibril deposition.


C1 axonemal microtubule

One of two microtubules present in the axonemal central pair. It is distinguishable from the C2 axonemal microtubule (also called C2 tubule) by the presence of differing protein components of the projections.


nuclear microtubule

Any microtubule in the nucleus of a cell.


trichome papilla

A plant cell papilla that is part of a trichome cell.


investment cone

A cytoskeletal part that consists of a microfilament-rich cone that forms round each nucleus in a spermatogenic cyst and translocates the length of the cyst during sperm individualization.


chiasma

A connection formed between chromatids, visible during meiosis, thought to be the point of the interchange involved in crossing-over.


neuromuscular junction of skeletal muscle fiber

A neuromuscular junction in which the target muscle cell is a skeletal muscle fiber.


SCF-Hrt3/Pof7 ubiquitin ligase complex

An SCF ubiquitin ligase complex in which the F-box protein is Hrt3 in S. cerevisiae (Pof7 in S. pombe).


yolk plasma

Discrete structures that partition the water-soluble portion of the yolk of oocytes and ova, which may or may not be membrane enclosed.


germ tube septin cap

A faint structure formed of septins found at the leading edge of growth in germ tubes of fungal cells growing filamentously. This cap of septins colocalizes with a region of the plasma membrane that is rich in ergosterol.


actin cytoskeleton of dendritic spine

The actin cytoskeleton that is part of a dendritic spine.


hyphae septin collar

A septin collar in pathogenic fungi involved in the constriction of hyphae at the plant plasmodesma enabling penetration of an adjacent cell.


prospore septin filament array

Arrays of septin filaments, or bars, found in a series of filamentous structures; observed in the prospore membrane during spore formation.


septin filament array

Arrays of septin filaments, or bars, found in a series of filamentous structures. Such structures have been observed in the prospore membrane during spore formation in S. cerevisiae and in the chlamydospore membrane during chlamydospore formation in C. albicans.


postsynaptic cytoskeleton

The portion of the cytoskeleton contained within the postsynapse.


postsynaptic septin cytoskeleton

The portion of the septin cytoskeleton contained within the postsynapse.


mating projection septin ring

A septin ring, i.e. a ring-shaped structure composed of septins and septin-associated proteins, located at the neck of a shmoo (mating projection). The septin ring in the neck of a shmoo may act as a barrier to localize mating factors in the shmoo tip.


postsynaptic intermediate filament cytoskeleton

The intermediate filament cytoskeleton that is part of a postsynapse.


septin ring

A tight ring-shaped structure that forms in the division plane at the site of cytokinesis; composed of members of the conserved family of filament-forming proteins called septins as well as septin-associated proteins. This type of septin structure is observed at the bud neck of budding fungal cells, at the site of cell division in animal cells, at the junction between the mother cell and a pseudohyphal projection, and also within hyphae of filamentous fungi at sites where a septum will form.


septin collar

A tubular, hourglass-shaped structure composed of highly ordered arrays of septin filaments; in budding yeast cells, the septin collar forms from the initial septin ring by expanding into the daughter cell.


postsynaptic actin cytoskeleton

The actin cytoskeleton that is part of a postsynapse.


germ tube septin ring

A tight ring-shaped structure that forms in the division plane within the germ tube of filamentous fungi at sites where a septum will form; composed of septins as well as septin-associated proteins.


split septin rings

A pair of rings that flank the site of cell division, formed by splitting of the septin ring (or collar) prior to cytokinesis; this double ring structure is thought to trap proteins needed for cytokinesis or the formation of the new membrane or cell wall between the two septin rings. Split septin rings are known to occur in budding yeast cells and probably occur in other cell types as well.


septin cytoskeleton

The part of the cytoskeleton (the internal framework of a cell) composed of septins and associated proteins. Includes septin cytoskeleton-associated complexes.


presynaptic actin cytoskeleton

The actin cytoskeleton that is part of a presynapse.


prospore septin ring

A tight ring-shaped structure that forms in the division plane at the site of cytokinesis in a prospore; composed of septins as well as septin-associated proteins.


chlamydospore septin filament array

Arrays of septin filaments, or bars, found in a series of filamentous structures. Observed in the chlamydospore membrane during chlamydospore formation.


neurofilament cytoskeleton

Intermediate filament cytoskeletal structure that is made up of neurofilaments. Neurofilaments are specialized intermediate filaments found in neurons.


hyphal septin cap

A faint structure formed of septins found at the leading edge of growth in hyphae of fungal cells growing filamentously. This cap of septins colocalizes with a region of the plasma membrane that is rich in ergosterol.


septin cap

A faint structure formed of septins found at the leading edge of growth in germ tubes and hyphae in fungal cells growing filamentously. This cap of septins colocalizes with a region of the plasma membrane that is rich in ergosterol.


pseudohyphal septin ring

A tight ring-shaped structure that forms in the division plane at the junction between the mother cell and a pseudohyphal projection; composed of septins as well as septin-associated proteins.


presynaptic cytoskeleton

The portion of the cytoskeleton contained within the presynapse.


cellular bud neck septin ring

A ring-shaped structure that forms at the site of cytokinesis in the bud neck of a budding cell; composed of members of the conserved family of filament forming proteins called septins as well as septin-associated proteins. In S. cerevisiae, this structure forms at the time of bud emergence and the septins show a high rate of exchange.


perinuclear theca

A condensed cytoplasmic structure that covers the nucleus of mammalian spermatozoa except for a narrow zone around the insertion of the tail. It shows two distinct regions, a subacrosomal layer and, continuing caudally beyond the acrosomic system, the postacrosomal sheath. The perinuclear theca has been considered a cytoskeletal scaffold responsible for maintaining the overall architecture of the mature sperm head; however, recent studies indicate that the bulk of its constituent proteins are not traditional cytoskeletal proteins but rather a variety of cytosolic proteins.


presynaptic intermediate filament cytoskeleton

The intermediate filament cytoskeleton that is part of a presynapse.


cytoskeleton of dendritic spine

The portion of the cytoskeleton that lies within a dendritic spine. The actin component of this cytoskeleton is involved in spine head remodeling in response to postsynaptic signaling.


hyphal septin ring

A tight ring-shaped structure that forms in the division plane within hyphae of filamentous fungi at sites where a septum will form; composed of septins as well as septin-associated proteins.


cellular bud neck split septin rings

Two separate septin rings that are formed from the septin collar at the time of cytokinesis in cells that divide by budding. These two rings are thought to delineate a special compartment in which factors involved in cytokinesis are concentrated.


spectrin-associated cytoskeleton

The part of the cytoskeleton composed of spectrin, protein 4.1 and ankyrin. Spectrin-associated cytoskeleton is associated with the plasma membrane.


medial cortex septin ring

A ring-shaped structure that forms at the medial cortex of a symmetrically dividing cell at the onset of cytokinesis; composed of members of the conserved family of filament forming proteins called septins as well as septin-associated proteins.


The portion of the spectrin-associated cytoskeleton contained within the postsynapse.


MsbA transporter complex

An ATP-binding cassette (ABC) transporter complex made up of a dimer of MsbA. Facilitates the export across the plasma membrane of, amongst others, lipid A and lipopolysaccharide. In contrast to most ABC transporter complexes, each chain of the homodimer contains both the transmembrane domain (TMD) and the cytoplasmic ATP-binding domain (NBD).


mitochondrial prohibitin complex

A complex composed of two proteins, prohibitin 1 and prohibitin 2 (PHB1/PHB-1 and PHB2/PHB-2) that is highly conserved amongst eukaryotes and associated with the inner mitochondrial membrane. The mitochondrial prohibitin complex is a macromolecular supercomplex composed of repeating heterodimeric subunits of PHB1 and PHB2. The mitochondrial prohibitin complex plays a role in a number of biological processes, including mitochondrial biogenesis and function, development, replicative senescence, and cell death.


dinoflagellate apical horn

A horn-shaped dinoflagellate apex found in thecate species.


host cell endocytic vesicle membrane

The lipid bilayer surrounding a host cell endocytic vesicle.


esterosome membrane

The lipid bilayer surrounding an esterosome. This membrane has characteristics of rough endoplasmic reticulum (RER) membranes.


BID-BCL-xl complex

A heterodimeric protein complex consisting of BID and BCL-xl, members of the Bcl-2 family of anti- and proapoptotic regulators.


Golgi medial cisterna

The middle Golgi cisterna (or cisternae).


oligosaccharyltransferase I complex

An oligosaccharyltransferase (OST) complex that contains at least seven polypeptides and is the major OST complex in mammalian cells. Of the three forms of mammalian OST complex identified, the OSTI complex has the weakest affinity for ribosomes.


glycolate oxidase complex

An enzyme complex that catalyzes the oxidation of 2-hydroxy acid to form 2-oxo acid and hydrogen peroxide (H2O2). The enzyme is a flavoprotein (FMN).


thioredoxin-disulfide reductase complex

A protein complex which is capable of thioredoxin-disulfide reductase activity.


connexin complex

An assembly of six molecules of connexin, made in the Golgi apparatus and subsequently transported to the plasma membrane, where docking of two connexons on apposed plasma membranes across the extracellular space forms a gap junction.


host cell Golgi apparatus

A compound membranous cytoplasmic organelle of eukaryotic host cells, consisting of flattened, ribosome-free vesicles arranged in a more or less regular stack.


MHC class Ib protein complex

A transmembrane protein complex composed of a MHC class Ib alpha chain and, in most cases, an invariant beta2-microglobin chain, and with or without a bound peptide or lipid antigen. Class Ib here refers to non-classical class I molecules, such as those of the CD1 or HLA-E gene families.


chromoplast inner membrane

The inner, i.e. lumen-facing, lipid bilayer of the chromoplast envelope; also faces the chromoplast stroma.


chromoplast membrane

Either of the lipid bilayers that surround a chromoplast and form the chromoplast envelope.


H zone

A relatively pale zone traversing the center of the A band of a sarcomere, visible in relaxed muscle fibers; consists of the central portion of thick (myosin) filaments that are not overlapped by thin (actin) filaments.


rixosome complex

A conserved RNA endonuclease complex required for spreading and epigenetic inheritance of heterochromatin. The rixosome contains six unique subunits: three structural subunits (Crb3, Rix1, and Ipi1) which form the core of the complex, and three catalytic subunits (the endonuclease Las1, the polynucleotide kinase Grc3, and the AAA-type ATPase Mdn1), which are involved in the processing of ribosomal RNA precursors. All subunits are essential for viability and are conserved from yeast to mammals, including humans.


collagen type IX trimer

A collagen heterotrimer containing type IX alpha chains in alpha1(IX)alpha2(IX)alpha3(IX) trimers; type IX collagen triple helices associate to form a structure that links glycosaminoglycans to type II collagen fibrils.


amyloplast

A plastid whose main function is to synthesize and store starch.


secondary cell wall

A plant cell wall that is no longer able to expand and so does not permit growth. Secondary cell walls contain less pectin that primary cell walls. The secondary cell is mostly composed of cellulose and is strengthened with lignin.


extrinsic component of periplasmic side of plasma membrane

The component of a plasma membrane consisting of gene products and protein complexes that are loosely bound to its periplasmic surface, but not integrated into the hydrophobic region.


hippocampal mossy fiber to CA3 synapse

One of the giant synapses that form between the mossy fiber axons of dentate gyrus granule cells and the large complex spines of CA3 pyramidal cells. It consists of a giant bouton known as the mossy fiber expansion, synapsed to the complex, multiheaded spine (thorny excresence) of a CA3 pyramidal cell.


left caudal basal body

Any ciliary basal body that is part of a left caudal flagellum found in Giardia species (trophozoite stage).


spindle pole centrosome

A centrosome from which one pole of a mitotic or meiotic spindle is organized.


CHOP-ATF4 complex

A heterodimeric transcription factor complex that is composed of CHOP (C/EBP homology protein, GADD153) and ATF4 (activating transcription factor 4, also known as cAMP response element binding protein-2/CREB-2) subunits.


G-protein beta/gamma-subunit complex

The heterodimer formed by the beta and gamma subunits of a heterotrimeric G protein, which dissociates from the alpha subunit upon guanine nuclotide exchange.


tissue

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Multicellular anatomical structure that consists of many cells of one or a few types, arranged in an extracellular matrix such that their long-range organisation is at least partly a repetition of their short-range organisation.


organism subdivision

Anatomical structure which is a subdivision of a whole organism, consisting of components of multiple anatomical systems, largely surrounded by a contiguous region of integument.


Digestive System Part

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A term that refers to any anatomic structure that is part of the digestive system.


Epithelium Part

Any component of the avascular cellular layers that cover body surfaces and cavities and may form glands.


Tissue Part

Any component of the anatomical structure consisting of similarly specialized cells and intercellular matrix, aggregated according to genetically determined spatial relationships, performing a specific function.


striated border microvillus layer

A microvillus layer that is striated and found in the intestine.


sexual spore wall

A specialized envelope lying outside the cell membrane of a spore derived from a product of meiosis.


spore wall

The specialized envelope lying outside the cell membrane of a spore.


asexual spore wall

A specialized envelope lying outside the cell membrane of a spore derived from an asexual process. Examples of this process are found in bacterial and fungal species.


ascospore wall

The specialized cell wall of the ascospore (spore), which is the product of meiotic division. Examples of this component are found in Fungi.


endospore external encapsulating structure

The structures that lie outside the inner membrane and surround the entire endospore; consists of a peptidoglycan-containing inner layer (the endospore cortex) surrounded by a multilayered proteinaceous coat. An exosporium may be present as an extreme outer layer.


MBF transcription complex

A protein complex that binds to the Mlu1 cell cycle box (MCB) promoter element, consensus sequence ACGCGN, and is involved in regulation of transcription during the G1/S transition of the cell cycle. In Saccharomyces, the complex contains a heterodimer of the DNA binding protein Mbp1p and the activator Swi6p, and is associated with additional proteins known as Nrm1p, Msa1p, and Msa2p; in Schizosaccharomyces the complex contains Res1p, Res2p, and Cdc10p.


cellular bud

A protuberance from a cell of an organism that reproduces by budding, which will grow larger and become a separate daughter cell after nuclear division, cytokinesis, and cell wall formation (when appropriate). The daughter cell may completely separate from the mother cell, or the mother and daughter cells may remain associated.


NarGHI complex

A heterotrimeric protein complex with iron-sulfur and molybdenum cofactors that functions as a terminal reductase in electron transport pathways that operate during anaerobic nitrate respiration. In E. coli electrons are passed from the FdnGHI complex to the NarGHI complex via menoquinone and menaquinol. Within NarGHI, electrons are passed from the two heme molecules in the NarI subunit down a Fe-S cluster chain in the NarH and NarG subunits to the Molybdenum cofactor, Mo-bisMGD, in the NarG subunit.


mitotic spindle assembly checkpoint MAD1-MAD2 complex

A protein complex involved in the assembly of the mitotic checkpoint complex that in turn inhibits the anaphase promoting complex/cyclosome (APC/C). The MAD1 dimer recruits the open form of MAD2 (O-MAD2) turning it into the closed form (C-MAD2) upon binding. C-MAD2 inhibits CDC20, a member of the APC/C, upon release from the MAD1-MAD2 complex.


Noc1p-Noc2p complex

A heterodimer associated with 90S and 66S preribosomes. Predominantly, but not exclusively, nucleolar; involved in ribosomal large subunit biogenesis.


A protein complex that is formed by the association of a heterodimeric interleukin-12 receptor complex with an interleukin-12 heterodimer.


thylakoid membrane

The pigmented membrane of any thylakoid.


photosynthetic membrane

A membrane enriched in complexes formed of reaction centers, accessory pigments and electron carriers, in which photosynthetic reactions take place.


cyanelle thylakoid membrane

The lipid bilayer membrane of any thylakoid within a cyanelle.


prothylakoid membrane

The membrane of prothylakoids, underdeveloped thylakoids found in etioplasts, lacking competent photosynthetic membranes.


chloroplast thylakoid membrane

The pigmented membrane of a chloroplast thylakoid. An example of this component is found in Arabidopsis thaliana.


plasma membrane-derived chromatophore membrane

The lipid bilayer associated with a plasma membrane-derived chromatophore; surrounds chromatophores that form complete vesicles.


plasma membrane-derived thylakoid membrane

The pigmented membrane of a plasma membrane-derived thylakoid.


organellar chromatophore thylakoid membrane

The lipid bilayer membrane of any thylakoid within an organellar chromatophore.


plastid thylakoid membrane

The lipid bilayer membrane of any thylakoid within a plastid.


infected host cell surface knob

Protrusion that develops in the plasma membrane of a parasitized erythrocyte. An example of this component is found in Plasmodium species.


microvillar actin bundle

A parallel bundle of actin filaments at the core of a microvillus.


parallel actin filament bundle

An actin filament bundle in which the filaments are tightly packed (approximately 10-20 nm apart) and oriented with the same polarity.


formin-nucleated actin cable

An actin filament bundle that consists of short filaments organized into bundles of uniform polarity, and is nucleated by formins. In fungal cells, myosin motors transport cargo along actin cables toward sites of polarized cell growth; actin cables may play a similar role in pollen tube growth.


actin filament bundle of filopodium

A parallel bundle of actin filaments that is part of filopodium. Filaments are oriented such that the plus (barbed) ends are at the tip of the protrusion, capped by a tip complex.


actin filament bundle of stereocilium

A bundle of hundreds of cross-linked actin filaments (an actin cable), that is the supporting structure of a stereocilium. Filaments are oriented such that the the plus (barbed) ends are at the tip of the protrusion and are capped by a tip complex which bridges to the plasma membrane.


actin filament bundle of actin-based cell projection

A bundle of cross-linked actin filaments that is part of an actin-based cell protrusion, in which filaments are oriented such that the plus (barbed) ends are at the tip of the protrusion, capped by a tip complex which stabilizes the filaments.


ficolin-1-rich granule membrane

The lipid bilayer surrounding a ficolin-1-rich granule.


clathrin-coated phagocytic vesicle membrane

The lipid bilayer surrounding a clathrin-coated phagocytic vesicle.


inter-Golgi transport vesicle membrane

The lipid bilayer surrounding a vesicle transporting substances within the Golgi.


outer acrosomal membrane

The acrosomal membrane region that underlies the plasma membrane of the sperm. This membrane fuses with the sperm plasma membrane as part of the acrosome reaction.


chromaffin granule membrane

The lipid bilayer surrounding a chromaffin granule, a specialized secretory vesicle found in the cells of adrenal glands and various other organs, which is concerned with the synthesis, storage, metabolism, and secretion of epinephrine and norepinephrine.


clathrin-coated endocytic vesicle membrane

The lipid bilayer surrounding a clathrin-coated endocytic vesicle.


specific granule membrane

The lipid bilayer surrounding a specific granule, a granule with a membranous, tubular internal structure, found primarily in mature neutrophil cells. Most are released into the extracellular fluid. Specific granules contain lactoferrin, lysozyme, vitamin B12 binding protein and elastase.


postsynaptic early endosome membrane

The lipid bilayer surrounding a postsynaptic early endosome.


organellar chromatophore inner membrane

The inner, i.e. lumen-facing, of the two lipid bilayers surrounding an organellar chromatophore.


postsynaptic endosome membrane

The lipid bilayer surrounding a postsynaptic endosome.


phagolysosome vesicle membrane

The lipid bylayer surrounding a phagolysosome.


macropinosome membrane

The lipid bilayer surrounding a macropinosome.


lamellar body membrane

The lipid bilayer surrounding a lamellar body. A lamellar body is a membrane-bounded organelle, specialized for the storage and secretion of various substances (surfactant phospholipids, glycoproteins and acid phosphates) which are arranged in the form of tightly packed, concentric, membrane sheets or lamellae. Has some similar properties to, but is distinct from, a lysosome.


platelet dense granule membrane

The lipid bilayer surrounding the platelet dense granule.


organellar chromatophore membrane

Either of the lipid bilayers that surround an organellar chromatophore.


presynaptic endosome membrane

The lipid bilayer surrounding a presynaptic endosome.


postsynaptic recycling endosome membrane

The lipid bilayer surrounding a postsynaptic recycling endosome.


azurophil granule membrane

The lipid bilayer surrounding an azurophil granule, a primary lysosomal granule found in neutrophil granulocytes that contains a wide range of hydrolytic enzymes and is released into the extracellular fluid.


trans-Golgi network transport vesicle membrane

The lipid bilayer surrounding a vesicle transporting substances between the trans-Golgi network and other parts of the cell.


platelet alpha granule membrane

The lipid bilayer surrounding the platelet alpha granule.


dense core granule membrane

The lipid bilayer surrounding a dense core granule.


endocytic vesicle membrane

The lipid bilayer surrounding an endocytic vesicle.


peribacteroid membrane

A membrane that surrounds one or more bacteroids (such as nitrogen-fixing bacteroids within legume root nodule cells).


COPI-coated vesicle membrane

The lipid bilayer surrounding a COPI-coated vesicle.


alveolar lamellar body membrane

The lipid bilayer surrounding an alveolar lamellar body, a specialized secretory organelle found in type II pneumocytes and involved in the synthesis, secretion, and reutilization of pulmonary surfactant.


early phagosome membrane

The lipid bilayer surrounding an early phagosome.


tertiary granule membrane

The lipid bilayer surrounding a tertiary granule.


endolysosome membrane

The lipid bilayer surrounding an endolysosome. An endolysosome is a transient hybrid organelle formed by fusion of a late endosome with a lysosome.


aleurone grain membrane

The lipid bilayer surrounding an aleurone grain.


epidermal lamellar body membrane

The lipid bilayer surrounding an epidermal lamellar body, a specialized secretory organelle found in keratinocytes and involved in the formation of an impermeable, lipid-containing membrane that serves as a water barrier and is required for correct skin barrier function.


gut granule membrane

The membrane of a gut granule, a lysosome-related organelle contained within the intestinal cells of the nematode C. elegans.


multivesicular body membrane

The lipid bilayer surrounding a multivesicular body.


clathrin-sculpted monoamine transport vesicle membrane

The lipid bilayer surrounding a clathrin-sculpted monoamine transport vesicle.


merozoite dense granule membrane

The lipid bilayer surrounding a dense granule of the type found in apicomplexan parasites.


inner acrosomal membrane

The acrosomal membrane region that underlies the acrosomal vesicle and is located toward the sperm nucleus. This region is responsible for molecular interactions allowing the sperm to penetrate the zona pellucida and fuses with the egg plasma membrane.


clathrin-sculpted glutamate transport vesicle membrane

The lipid bilayer surrounding a clathrin-sculpted glutamate transport vesicle.


multivesicular body, internal vesicle membrane

The lipid bilayer surrounding a multivesicular body internal vesicle.


organellar chromatophore outer membrane

The outer, i.e. cytoplasm-facing, of the two lipid bilayers surrounding an organellar chromatophore.


Golgi to ER transport vesicle membrane

The lipid bilayer surrounding a vesicle transporting substances from the Golgi to the ER.


phagolysosome membrane

The lipid bilayer surrounding a phagolysosome.


exocytic vesicle membrane

The lipid bilayer surrounding an exocytic vesicle.


clathrin-sculpted gamma-aminobutyric acid transport vesicle membrane

The lipid bilayer surrounding a clathrin-sculpted gamma-aminobutyric acid transport vesicle.


rod photoreceptor disc membrane

Stack of disc membranes located inside a rod photoreceptor outer segment, and containing densely packed molecules of rhodopsin photoreceptor proteins that traverse the lipid bilayer. It is thought that rod disc membranes arise as evaginations of the ciliary membrane near the base of the outer segment, which then become completely separated from the ciliary membrane, during the development of the rod outer segment.


contractile vacuolar membrane

The lipid bilayer surrounding the contractile vacuole.


Cvt vesicle membrane

Either of the two lipid bilayers surrounding a Cvt vesicle, a vesicle that functions in the cytoplasm-to-vacuole targeting (Cvt) pathway.


phagocytic vesicle membrane

The lipid bilayer surrounding a phagocytic vesicle.


chitosome membrane

The lipid bilayer surrounding a chitosome.


clathrin-coated vesicle membrane

The lipid bilayer surrounding a clathrin-coated vesicle.


foot layer

The inner layer of the ectexine.


protein C inhibitor-KLK3 complex

A heterodimeric protein complex that contains protein C inhibitor (SERPINA5) and prostate-specific antigen (KLK3); formation of the complex inhibits the serine protease activity of prostate-specific antigen.


peptidase inhibitor complex

A protein complex which is capable of peptidase inhibitor activity.


protein C inhibitor-PLAU complex

A heterodimeric protein complex that contains protein C inhibitor (SERPINA5) and urokinase-type plasminogen activator (PLAU); formation of the complex inhibits the serine protease activity of urokinase-type plasminogen activator.


protein C inhibitor-coagulation factor V complex

A heterodimeric protein complex that contains protein C inhibitor (SERPINA5) and coagulation factor V (F5); formation of the complex inhibits the serine protease activity of coagulation factor V.


protein C inhibitor-thrombin complex

A heterodimeric protein complex that contains protein C inhibitor (SERPINA5) and thrombin (F2); formation of the complex inhibits the serine protease activity of thrombin.


protease inhibitor complex

A heterodimeric protein complex that contains a protease inhibitor and a protease; formation of the complex inhibits protease activity.


protein C inhibitor-coagulation factor XI complex

A heterodimeric protein complex that contains protein C inhibitor (SERPINA5) and coagulation factor XI (F11); formation of the complex inhibits the serine protease activity of coagulation factor XI.


protein C inhibitor-acrosin complex

A heterodimeric protein complex of protein C inhibitor (SERPINA5) and acrosin; formation of the complex inhibits the protease activity of acrosin.


serine protease inhibitor complex

A heterodimeric protein complex that contains a serine protease inhibitor and a protease; formation of the complex inhibits serine protease activity.


protein C inhibitor-coagulation factor Xa complex

A heterodimeric protein complex that contains protein C inhibitor (SERPINA5) and coagulation factor Xa (F10); formation of the complex inhibits the serine protease activity of coagulation factor Xa.


protein C inhibitor-TMPRSS11E complex

A heterodimeric protein complex that contains protein C inhibitor (SERPINA5) and transmembrane protease serine 11E (TMPRSS11E); formation of the complex inhibits the serine protease activity of transmembrane protease serine 11E.


protein C inhibitor-TMPRSS7 complex

A heterodimeric protein complex that contains protein C inhibitor (SERPINA5) and transmembrane protease serine 7 (TMPRSS7); formation of the complex inhibits the serine protease activity of transmembrane protease serine 7.


germ plasm

Differentiated cytoplasm associated with a pole of an oocyte, egg or early embryo that will be inherited by the cells that will give rise to the germ line.


cytoplasmic periphery of the nuclear pore complex

Cytoplasm situated in close proximity to a nuclear pore complex.


alphaV-beta3 integrin-NOV complex

A protein complex that consists of an alphaV-beta3 integrin complex bound to the extracellular matrix protein NOV.


integrin alphaL-beta2 complex

An integrin complex that comprises one alphaL subunit and one beta2 subunit.


tRNA-splicing ligase complex

A protein complex that catalyzes the ligation of cleaved pre-tRNAs by directly joining spliced tRNA halves to mature-sized tRNAs by incorporating the precursor-derived splice junction phosphate into the mature tRNA as a canonical 3',5'-phosphodiester.


MMXD complex

A protein complex that contains the proteins MMS19, MIP18 and XPD, localizes to mitotic spindle during mitosis, and is required for proper chromosome segregation.


spermatoproteasome complex

A proteasome specifically found in mammalian testis. Contains the proteasome activator PA200 in the regulatory particle, and beta1i, beta2i, beta5i and/or alpha4s in the core (20S) subunit. Beta1i, beta2i and beta5i are inducible catalytic subunits, closely related to beta1, beta2 and beta5. Alpha4s is a sperm-specific 20S subunit, but unlike other alternative 20S subunits alpha4s lies in the outer alpha-ring and lacks catalytic activity.


caspase complex

A protein complex that contains one or more cysteine-type endopeptidases (also called caspases), which give the complex a peptidase activity with specificity for the hydrolysis of aspartyl bonds. These complexes may be involved e.g. in apoptotic or inflammation processes.


serine-type peptidase complex

A protein complex which is capable of serine-type peptidase activity.


HslUV protease complex

A protein complex that possesses ATP-dependent protease activity; consists of an ATPase large subunit with homology to other ClpX family ATPases and a peptidase small subunit related to the proteasomal beta-subunits of eukaryotes. In the E. coli complex, a double ring-shaped homohexamer of HslV is capped on each side by a ring-shaped HslU homohexamer.


nuclear proteasome complex

A proteasome found in the nucleus of a cell.


GPI-anchor transamidase complex

An enzyme complex which in humans and yeast consists of at least five proteins; for example, the complex contains GAA1, GPI8, PIG-S, PIG-U, and PIG-T in human, and Gaa1p, Gab1p, Gpi8p, Gpi16p, and Gpi17p in yeast. Catalyzes the posttranslational attachment of the carboxy-terminus of a precursor protein to a GPI-anchor.


PNGase complex

A protein complex responsible for the catalysis of the reaction: 4-N-(N-acetyl-D-glucosaminyl)-protein + H2O = N-acetyl-beta-D-glucosaminylamine + peptide L-aspartate. This reaction is the hydrolysis of an N4-(acetyl-beta-D-glucosaminyl)asparagine residue in which the N-acetyl-D-glucosamine residue may be further glycosylated, to yield a (substituted) N-acetyl-beta-D-glucosaminylamine and the peptide containing an aspartic residue.


m-AAA complex

Protease complex of the mitochondrial inner membrane that is involved in mitochondrial protein turnover and in processing of proteins imported into mitochondria.


separase-securin complex

A protein complex that includes separase (a protease which cleaves cohesin as part of chromosome separation) and securin, a protease inhibitor. Chromosome separation is inhibited until securin is degraded by the Anaphase Promoting Complex (APC).


signal peptidase complex

A protein complex that is located in the endoplasmic reticulum membrane and cleaves the signal sequence from precursor proteins following their transport out of the cytoplasmic space.


cytosolic proteasome complex

A proteasome complex found in the cytosol of a cell.


H-gal-GP complex

A membrane glycoprotein complex with aspartyl proteinase and metalloproteinase activity which is expressed in the gut. An example of this is found in the nematode Haemonchus contortus.


calpain complex

A calcium-dependent protease complex that processes its substrate by limited proteolysis rather than degrading it. In some cases limited proteolysis is required for the activation of its substrate.


serine-type endopeptidase complex

A protein complex which is capable of serine-type endopeptidase activity.


cerebellar Golgi cell to granule cell synapse

A synapse formed by a cerebellar Golgi cell synapsing on to a cerebellar granule cell.


presynaptic periactive zone

A region that surrounds the active zone of the presynaptic plasma membrane, and is specialized for the control of synaptic development.


multiple synapse bouton, contacting single dendrite

A single axon terminal bouton making contact onto two or more dendritic spines protruding from the same dendrite.


tripartite attachment complex

A three-part cytoskeletal structure in kinetoplastid species linking mitochondrial DNA organised in a kinetoplast through the mitochondrial membranes to the basal body.


dense body

An electron dense body which may contain granules.


nitrite reductase complex [NAD(P)H]

Complex that possesses nitrite reductase [NAD(P)H] activity.


G protein-coupled GABA receptor complex

A protein complex which is capable of G protein-coupled GABA receptor activity. In human, it is usually a heterodimer composed of GABA-B receptor subunits 1 and 2.


CST complex

A complex formed by the association of Cdc13 (CTC1 in mammals) with Stn1 in yeast (OBFC1 in mammals) and Ten1 protein (also TEN1 in mammals) with single-stranded telomeric DNA. The CST complex plays a role in telomere protection.


primary endosperm nucleus

Nucleus resulting from the fusion of the male gamete and two polar nuclei in the central cell of the embryo sac.


matrilin complex

A cartilage extracellular matrix complex that mediates interactions between major components of the extracellular matrix such as collagens and proteoglycans and contributes to their fibrillar network. Exists as an obligate homotrimer.


alphaV-beta3 integrin-LPP3 complex

A protein complex that consists of an alphaV-beta3 integrin complex bound to lipid phosphate phosphohydrolase-3.


endocytic patch

The part of the cell cortex consisting of an aggregation of proteins that will give rise to an endocytic vesicle.


intracellular cyclic nucleotide activated cation channel complex

A protein complex that forms a transmembrane channel through which cations ions may pass in response to an intracellular cyclic nucleotide binding to the channel complex or one of its constituent parts.


voltage-gated potassium channel complex

A protein complex that forms a transmembrane channel through which potassium ions may cross a cell membrane in response to changes in membrane potential.


uniplex complex

A calcium channel complex in the mitochondrial inner membrane capable of highly-selective calcium channel activity. Its components include the EF-hand-containing proteins mitochondrial calcium uptake 1 (MICU1) and MICU2, the pore-forming subunit mitochondrial calcium uniporter (MCU) and its paralog MCUb, and the MCU regulator EMRE.


HCN channel complex

A cation ion channel with a preference for K+ over Na+ ions, which is activated by membrane hyperpolarization, and consists of a tetramer of HCN family members. Some members of this family (HCN1, HCN2 and HCN4) are also activated when cAMP binds to their cyclic nucleotide binding domain (CNBD). Channel complexes of this family play an important role in the control of pacemaker activity in the heart.


Kv4.2-KChIP1 channel complex

A voltage-gated potassium channel complex that contains the Kv channel interacting protein KChIP1 associated with the channel via interaction with the Kv alpha subunit 4.2.


Kir2 inward rectifier potassium channel complex

A inward rectifier potassium channel complex. Homo- or heterotetramer composed of subunits of the eukaryotic Kir2 protein family. Plays a key role in maintaining the correct resting potential in eukaryotic cells.


inward rectifying potassium channel

A protein complex that comprises four pore-forming (Kir6.x) and four regulatory sulphonylurea receptor (SURx) subunits and forms a transmembrane channel through which ions may pass. The opening and closing of the channel is regulated by ATP: binding of ATP to the Kir6.x subunit inhibits channel activity, whereas binding of Mg2+-complexed ATP or ADP to the SURx subunit stimulates channel activity.


Kv4.2-KChIP3 channel complex

A voltage-gated potassium channel complex that contains the Kv channel interacting protein KChIP3 associated with the channel via interaction with the Kv alpha subunit 4.2.


mitochondrial ATP-gated potassium channel complex

A protein-containing complex that is capable of the ATP-dependent diffusion of a potassium ion across the mitochondrial inner membrane.


voltage-gated sodium channel complex

A sodium channel in a cell membrane whose opening is governed by the membrane potential.


ryanodine receptor complex

A voltage-gated calcium-release channel complex of the sarcoplasmic or endoplasmic reticulum. It plays an important role in the excitation-contraction (E-C) coupling of muscle cells. RyR comprises a family of ryanodine receptors, widely expressed throughout the animal kingdom.


L-type voltage-gated calcium channel complex

A type of voltage-dependent calcium channel responsible for excitation-contraction coupling of skeletal, smooth, and cardiac muscle. 'L' stands for 'long-lasting' referring to the length of activation.


potassium channel complex

An ion channel complex through which potassium ions pass.


serotonin-activated cation-selective channel complex

A protein complex which is capable of serotonin-activated cation-selective channel activity. Mainly found in pre- and postsynaptic membranes of the brain and gastrointestinal tract. Depending on its location it transports Ca2+, Mg2+, Na+ or K+. It is always a pentamer, containing at least the 5HT3A subunit forming 5HT3A homopentamers or 5HT3A/B heteropentamers. In human, 5HT3A/C, A/D and A/E heteropentamers also exist.


inward rectifier potassium channel complex

A protein complex which is capable of inward rectifier potassium channel activity.


Kv4.2-KChIP2 channel complex

A voltage-gated potassium channel complex that contains the Kv channel interacting protein KChIP2 associated with the channel via interaction with the Kv alpha subunit 4.2.


kainate selective glutamate receptor complex

An assembly of four or five subunits which form a structure with an extracellular N-terminus and a large loop that together form the ligand binding domain. The C-terminus is intracellular. The ionotropic glutamate receptor complex itself acts as a ligand gated ion channel; on binding glutamate, charged ions pass through a channel in the center of the receptor complex. Kainate receptors are multimeric assemblies of GluK1-3 (also called GluR5-7), GluK4 (KA1) and GluK5 (KA2) subunits.


Kv4.3-DPP10 channel complex

A voltage-gated potassium channel complex that contains the peptidase-related protein DPP10 associated with the channel via interaction with the Kv alpha subunit 4.3.


I(KACh) inward rectifier potassium channel complex

An inward rectifier potassium channel complex expressed in cardiac muscle, specifically the sinoatrial node and atria, where it controls the heart rate, via regulation by G protein-coupled receptor signaling. In mammals it is composed of GIRK1 (or Kir3.1) and GIRK4 (or Kir3.4) subunits.


Kv4.1-DPP10 channel complex

A voltage-gated potassium channel complex that contains the peptidase-related protein DPP10 associated with the channel via interaction with the Kv alpha subunit 4.1.


Kv4.3-DPP6 channel complex

A voltage-gated potassium channel complex that contains the peptidase-related protein DPP6 associated with the channel via interaction with the Kv alpha subunit 4.3.


Kv4.2-Kv4.3 channel complex

A voltage-gated potassium channel complex that contains the Kv alpha subunits 4.2 and 4.3.


Kv4.2-KChIP4 channel complex

A voltage-gated potassium channel complex that contains the Kv channel interacting protein KChIP4 associated with the channel via interaction with the Kv alpha subunit 4.2.


light-activated voltage-gated calcium channel complex

A protein complex that forms a transmembrane channel through which calcium ions may cross a cell membrane in response to changes in membrane potential generated in response to a light stimulus.


Kv4.2-DPP6 channel complex

A voltage-gated potassium channel complex that contains the peptidase-related protein DPP6 associated with the channel via interaction with the Kv alpha subunit 4.2.


Kv4.1-DPP6 channel complex

A voltage-gated potassium channel complex that contains the peptidase-related protein DPP6 associated with the channel via interaction with the Kv alpha subunit 4.1.


A SNARE complex that contains cellubrevin (VAMP3), VAMP4, endobrevin (VAMP8), and syntaxin 6 (or orthologs thereof).


flagella connector

A mobile transmembrane junction at the tip of the flagellum of some kinetoplastid species linking the tip of a new growing flagellum to an older flagellum.


TRAPPI protein complex

A complex that tethers COPII vesicles at ER-Golgi intermediate compartment. Its role in this part of the vesicular transport may start at the ER exit sites. Binds to a component of the COPII coat. In yeast it includes the following subunits: Bet3 (as homodimer), Bet5, Trs20, Trs23, Trs31, Trs33 which are regarded as the core subunits of all TRAPP complexes in yeast.


BIM-BCL-2 complex

A heterodimeric protein complex consisting of BIM and BCL-2, members of the Bcl-2 family of anti- and proapoptotic regulators.


host cell nuclear envelope

The double lipid bilayer enclosing the host nucleus and separating its contents from the rest of the host cytoplasm; includes the intermembrane space, a gap of width 20-40 nm (also called the perinuclear space).


3-methylcrotonyl-CoA carboxylase complex, mitochondrial

A mitochondrial protein complex which is capable of 3-methylcrotonyl-CoA carboxylase activity. In mammals, at least, consists as a dodecamer of 6 alpha and 6 beta subunits. MCCC-alpha has a covalently bound biotin essential for the ATP-dependent carboxylation. MCCC-beta possesses carboxyltransferase activity which presumably is essential for binding to 3-methylcrotonyl-CoA.


cytosolic creatine kinase complex

A dimeric protein complex having creatine kinase activity.


cellulose microfibril

A microfibril composed of cellulose arranged in orthogonal layers. Cellulose is a straight chain polysaccharide composed of B(14) linked glucose subunits. It is a major component of plant cell walls. Higher plant microfibrils are about 10nm in diameter and extremely long in relation to their width. The cellulose molecules are oriented parallel to the long axis of the microfibril in a paracrystalline array, which provides great tensile strength. The microfibrils are held in place by the wall matrix and their orientation is closely controlled by the cell.


integrin alpha6-beta4 complex

An integrin complex that comprises one alpha6 subunit and one beta4 subunit.


neck portion of tanycyte

Elongated portion of a tanycyte that sticks into the periventricular layer of neuropil where it appears to contact a blood vessel; characterized by numerous cytoplasmic extensions. A tanycyte is a specialized elongated ventricular ependymal cell that has processes that extend to the outer, or pial, surface of the CNS.


lamellipodium membrane

The portion of the plasma membrane surrounding a lamellipodium.


MAD1 complex

A protein complex involved in the assembly of the mitotic checkpoint complex that in turn inhibits the anaphase promoting complex/cyclosome (APC/C).


chloroplast chromosome

A circular DNA molecule containing chloroplast encoded genes.


plastid chromosome

A circular DNA molecule containing plastid encoded genes.


phenylalanine-tRNA ligase complex

An enzyme complex that catalyzes the ligation of phenylalanine to tRNA(Phe), forming L-phenylalanyl-tRNA(Phe).


IgX immunoglobulin complex

A protein complex composed of two identical immunoglobulin heavy chains of the IgX isotype and two identical immunoglobulin light chains, held together by disulfide bonds. An IgX immunoglobulin complex may be embedded in the plasma membrane or present in the extracellular space, in mucosal areas or other tissues, or circulating in the blood or lymph.


somatic spine

Spine emanating from the cell soma of a neuron.


nuclear membrane microtubule tethering complex

A nuclear membrane protein complex which connects the nuclear outer and inner membranes together, and links thereby links the nuclear lumen to cytoplasmic microtubules.


mitotic nuclear membrane microtubule tethering complex

A protein complex capable of interacting with the spindle pole body and the nuclear envelope, in order to embed the spindle pole body in the nuclear envelope at fusion sites of the inner and outer nuclear membrane.


glycinergic synapse

A synapse that uses glycine as a neurotransmitter.


PCSK9-LDLR complex

A protein complex consisting of the serine protease PCSK9 (proprotein convertase subtilisin/kexin-9) and a low-density lipoprotein receptor (LDLR). Interaction typically occurs through the epidermal growth factor-like repeat A (EGF-A) domain of the LDLR, and complex formation promotes degradation of the LDLR through the endosome/lysosome pathway.


platelet dense tubular network

A network of membrane-bounded compartments found in blood platelets, where they regulate platelet activation by sequestering or releasing calcium. The dense tubular network exists as thin elongated membranes in resting platelets, and undergoes a major ultrastructural change, to a rounded vesicular form, upon addition of thrombin.


cytoplasmic replication fork

The Y-shaped region of a cytoplasmic replicating DNA molecule, resulting from the separation of the DNA strands and in which the synthesis of new strands takes place. Also includes associated protein complexes.


protein phosphatase type 2A complex

A protein complex that has protein serine/threonine phosphatase activity that is polycation-stimulated (PCS), being directly stimulated by protamine, polylysine, or histone H1; it constitutes a subclass of several enzymes activated by different histones and polylysine, and consists of catalytic, scaffolding, and regulatory subunits. The catalytic and scaffolding subunits form the core enzyme, and the holoenzyme also includes the regulatory subunit.


host cell lysosomal membrane

The lipid bilayer surrounding the host cell lysosome and separating its contents from the host cell cytoplasm.


cytochrome b6f complex

Complex that transfers electrons from reduced plastoquinone to oxidized plastocyanin and translocates protons from the stroma to the lumen. The complex contains a core structure of three catalytic subunits: cytochrome b, the Rieske iron sulfur protein (ISP), and cytochrome f, which are arranged in an integral membrane-bound dimeric complex; additional subunits are present, and vary among different species.


WASH complex

A protein complex that localizes at the surface of endosomes, where it recruits and activates the Arp2/3 complex to induce actin polymerization. In human, the WASH complex is composed of F-actin-capping protein subunits alpha and beta, WASH1, FAM21, KIAA1033, KIAA0196 and CCDC53.


oligosaccharyltransferase III complex

An oligosaccharyltransferase (OST) complex that contains the seven polypeptides found in OST complex I, plus heterotrimeric Sec61alpha-beta-gamma and the tetrameric TRAP complex. Of the three forms of mammalian OST complexes identified, the OSTIII complex has the strongest affinity for ribosomes.


cellular birth scar

Crater-like ring of chitinous scar tissue located on the surface of the daughter cell, in budding fungi, at the site of separation from the mother cell. It is formed after the newly emerged daughter cell separates, thereby marking the site of cytokinesis and septation.


cell cortex of growing cell tip

Any cell cortex that is part of a growing cell tip.


posterior cell cortex

The region that lies just beneath the plasma membrane in the part of a cell that is closest to the posterior as defined by the developing, or existing, anterior/posterior axis.


dendritic spine cytoplasm

The region of the neuronal cytoplasm located in dendritic spines.


lateral cell cortex

The region directly beneath the plasma membrane of the lateral portion of the cell.


pole plasm

Differentiated cytoplasm associated with a pole (animal, vegetal, anterior, or posterior) of an oocyte, egg or early embryo.


apical cortex

The region that lies just beneath the plasma membrane on the apical edge of a cell.


presynaptic endocytic zone cytoplasmic component

The cytoplasmic component of the presynaptic endocytic zone.


dendrite cytoplasm

All of the contents of a dendrite, excluding the surrounding plasma membrane.


equatorial cell cortex

The region of the cell cortex in a mitotically dividing cell that flanks the central spindle and corresponds to the site of actomyosin ring formation that results in cleavage furrow formation and ingression.


presynaptic active zone cytoplasmic component

A specialized region below the presynaptic membrane, characterized by electron-dense material, a specialized cytoskeletal matrix and accumulated (associated) synaptic vesicles.


cell cortex of cell tip

The region directly beneath the plasma membrane at the cell tip. The cell tip is the region at either end of the longest axis of a cylindrical or elongated cell.


cell cortex region

The complete extent of cell cortex that underlies some some region of the plasma membrane.


medial cortex

A medial cortical band overlaying the nucleus which acts as a landmark for contractile ring positioning and plays a role in cell cycle regulation.


ooplasm

The cytoplasm of an ovum.


postsynaptic endocytic zone cytoplasmic component

The cytoplasmic component of the postsynaptic endocytic zone.


cell leading edge cell cortex

The cell cortex of the leading edge of a cell.


apicomedial cortex

The region that lies just beneath the plasma membrane in the middle of the apical edge of a cell.


basal cortex

The region that lies just beneath the plasma membrane on the basal edge of a cell.


anterior cell cortex

The region that lies just beneath the plasma membrane in the part of a cell that is closest to the anterior as defined by the developing, or existing, anterior/posterior axis.


neuron projection cytoplasm

All of the contents of a plasma membrane bounded neuron projection, excluding the plasma membrane surrounding the projection.


sarcoplasm

The cytoplasm of a muscle cell; includes the sarcoplasmic reticulum.


cell cortex of non-growing cell tip

The region directly beneath the plasma membrane at the cell tip at which no growth takes place.


organellar small ribosomal subunit

The smaller of the two subunits of an organellar ribosome.


chloroplast small ribosomal subunit

The small subunit of a ribosome contained within a chloroplast.


plastid small ribosomal subunit

The smaller of the two subunits of a plastid ribosome.


dinoflagellate hypocone

The part of a dinoflagellate cell below the cingulum; also referred to as the posterior portion of a dinoflagellate cell. It is separated from the epicone by the cingulum.


Cul4B-RING E3 ubiquitin ligase complex

A ubiquitin ligase complex in which a cullin from the Cul4B subfamily and a RING domain protein form the catalytic core; substrate specificity is conferred by unknown subunits.


CLRC complex

An cullin-dependent E3 ubiquitin ligase/histone H3-K9 methyltransferase complex essential for heterochromatin assembly by RNAi.


cytosolic alpha-ketoglutarate dehydrogenase complex

Cytosolic complex that possesses alpha-ketoglutarate dehydrogenase activity.


nuclear outer membrane

The outer, i.e. cytoplasm-facing, lipid bilayer of the nuclear envelope; continuous with the endoplasmic reticulum of the cell and sometimes studded with ribosomes.


Par3-APC-KIF3A complex

A protein complex that contains Par3, the tumor suppressor protein adenomatous polyposis coli (APC), and the kinesin-related protein KIF3A; involved in establishing neuronal cell polarity.


plasma membrane respiratory chain complex III

A part of the respiratory chain located in the plasma membrane, containing about 10 polypeptide subunits including four redox centers: cytochrome b/b6, cytochrome c1 and an 2Fe-2S cluster. Catalyzes the oxidation of ubiquinol by oxidized cytochrome c1. Examples of this component are found in bacterial species.


radial spoke base 2

The short portion of the radial spoke 2 (RS2) that is directly anchored to the A microtubule of an axonemal microtubule doublet.


Heterodimeric complex that catalyzes the pyrophosphate-dependent phosphorylation of D-fructose 6-phosphate into D-fructose 1,6-bisphosphate.


germ tube

The slender tubular outgrowth first produced by most spores in germination.


Lsm2-8 complex

A heteroheptameric, nuclear protein complex composed of Lsm2, Lsm3, Lsm4, Lsm5, Lsm6, Lsm7, and Lsm8, or orthologs thereof, that selectively binds to snRNAs, in particular U6 or U6atac snRNAs, and also to unspliced transcripts localized within the nucleus.


NatB complex

A conserved complex that catalyzes the transfer of an acetyl group to the N-terminal residue of a protein acceptor molecule that has a Met-Glu, Met-Asp, Met-Asn, or Met-Met N-terminus. In Saccharomyces the complex includes Nat3p and Mdm20p.


B-WICH complex

A chromatin remodeling complex that positively regulates histone H3 acetylation, in particular H3K9, by recruiting histone acetyltransferases to rDNA gene regions. Located in the nucleolus where it assembles on RNA Polymerase I (Pol I) and possibly on RNA Polymerase III (Pol III) promoter and coding regions during early G1 phase and activates the post-initiation phases of Pol I transcription. May also activate RNA Polymerase II (Pol II) gene transcription. In mammals, B-WICH contains the WICH complex core of BAZ1B and SMARCA5, additional protein subunits and possibly rRNAs. Although it contains several catalytic subunits it is not clear which functions are carried out by the complex itself.


RSF complex

An ISWI complex that contains an ATPase subunit of the ISWI family (SNF2H in mammals) and an RSF1 homolog. It mediates nucleosome deposition and generates regularly spaced nucleosome arrays. In mammals, RSF is involved in regulation of transcription from RNA polymerase II promoters).


NoRC complex

An ISWI complex that contains an ATPase subunit of the ISWI family (specifically SNF2H in mammals, which contain two ISWI homologs) and a Tip5 homolog. In mammals, NoRC is involved in regulation of transcription from RNAP I and RNA polymerase III promoters.


Isw1a complex

An Isw1 complex that binds DNA and has nucleosome-stimulated ATPase activity. In S. cerevisiae, contains an Isw1p ATPase subunit in complex with Ioc3p.


mBAF complex

A muscle cell-specific SWI/SNF-type complex that contains eight to fourteen proteins, including both conserved (core) and nonconserved components; contains the ATPase product of either the SMARCA4/BAF190A/BRG1 gene, the mammalian ortholog of the yeast SNF2 gene, or the SMARCA2/BAF190B/BRM gene, the mammalian ortholog of the Drosophila brm (brahma) gene, or an ortholog of either of these genes, and the muscle-specific product of the DPF3/BAF45C gene or an ortholog thereof.


Isw1 complex

A protein complex that contains an Isw1 subunit from the ISWI-family of ATPases and acts to modify chromatin structure.


Isw1b complex

An Isw1 complex that binds DNA and has nucleosome-stimulated ATPase activity. In S. cerevisiae, contains an Isw1p ATPase subunit in complex with Ioc2p and Ioc4p.


SHREC complex

A histone deacetylase complex that contains a core of four proteins -- Clr1, Clr2, Clr3, and Mit1 in fission yeast -- and localizes to all heterochromatic regions in the genome as well as some euchromatic sites. The complex is involved in regulating nucleosome positioning to assemble higher-order chromatin structures.


ACF complex

An ISWI complex that contains an ATPase subunit of the ISWI family (SNF2H in mammals, Isw2 in S. cerevisiae), an ACF1 homolog, and generally no other subunits, though Xenopus is an exception with a third non-conserved subunit. ACF plays roles in regulation of RNA polymerase II transcription and in DNA replication and repair.


archaeal proton-transporting A-type ATPase complex

A large proton-transporting two-sector ATPase protein complex that catalyzes the synthesis or hydrolysis of ATP by a rotational mechanism, coupled to the transport of protons across a membrane and is found in Archaea.


RSC-type complex

A SWI/SNF-type complex that contains a bromodomain containing-protein, such as yeast Rsc1 or Rsc4 or mammalian PB1/BAF180. The RSC complex is generally recruited to RNA polymerase III promoters and is specifically recruited to RNA polymerase II promoters by transcriptional activators and repressors; it is also involved in non-homologous end joining.


nBAF complex

A SWI/SNF-type complex that is found in post-mitotic neurons, and in human contains actin and proteins encoded by the ARID1A/BAF250A or ARID1B/BAF250B, SMARCD1/BAF60A, SMARCD3/BAF60C, SMARCA2/BRM/BAF190B, SMARCA4/BRG1/BAF190A, SMARCB1/BAF47, SMARCC1/BAF155, SMARCE1/BAF57, SMARCC2/BAF170, DPF1/BAF45B, DPF3/BAF45C, ACTL6B/BAF53B genes. The nBAF complex along with CREST plays a role regulating the activity of genes essential for dendrite growth.


CERF complex

An ISWI complex that contains an ATPase subunit of the ISWI family (specifically SNF2L in mammals, which contain two ISWI homologs) and a CECR2 homolog. In mammals, CERF is involved in regulation of transcription from RNA polymerase II promoters.


proton-transporting V-type ATPase complex

A proton-transporting two-sector ATPase complex that couples ATP hydrolysis to the transport of protons across a concentration gradient. The resulting transmembrane electrochemical potential of H+ is used to drive a variety of (i) secondary active transport systems via H+-dependent symporters and antiporters and (ii) channel-mediated transport systems. The complex comprises a membrane sector (V0) that carries out proton transport and a cytoplasmic compartment sector (V1) that catalyzes ATP hydrolysis. V-type ATPases are found in the membranes of organelles such as vacuoles, endosomes, and lysosomes, and in the plasma membrane.


npBAF complex

A SWI/SNF-type complex that is found in neural stem or progenitor cells, and in human contains actin and proteins encoded by the ARID1A/BAF250A or ARID1B/BAF250B, SMARCD1/BAF60A, SMARCD3/BAF60C, SMARCA2/BRM/BAF190B, SMARCA4/BRG1/BAF190A, SMARCB1/BAF47, SMARCC1/BAF155, SMARCE1/BAF57, SMARCC2/BAF170, PHF10/BAF45A, ACTL6A/BAF53A genes. The npBAF complex is essential for the self-renewal/proliferative capacity of the multipotent neural stem cells.


plasma membrane proton-transporting V-type ATPase complex

A proton-transporting two-sector ATPase complex found in the plasma membrane.


esBAF complex

An embryonic stem cell-specific SWI/SNF-type complex that contains eight or nine proteins, including both conserved (core) and nonconserved components; contains the ATPase product of either the SMARCA4/BAF190A/BRG1 gene, the mammalian ortholog of the yeast SNF2 gene, or an ortholog thereof. Compared to many other BAF complexes never contains ACTL6B/BAF53B, ARID1B/BAF250B, SMARCA2/BRM, SMARCC2/BAF170 or SMARCD3/BAF60C but contains PHF10/BAF45A, DPF2/BAF45D and possibly one of BCL7A/B/C.


WICH complex

An ISWI complex that contains an ATPase subunit of the ISWI family (specifically SNF2H in mammals, which contain two ISWI homologs) and WSTF (Williams Syndrome Transcription Factor). WICH plays roles in regulation of RNAP I and III transcription and in DNA replication and repair.


plasma membrane proton-transporting ATP synthase complex

A proton-transporting ATP synthase complex found in the plasma membrane. Examples of this component are found in Bacterial species.


ESCRT IV complex

An ESCRT complex that has AAA-ATPase activity and is involved in ESCRT-mediated intralumenal vesicle formation and the final stages of cytokinesis. The complex catalyzes disassembly of the ESCRT III filament around the neck of the budding vesicle in an ATP-driven reaction, resulting in membrane scission and recycling of the ESCRT III components back to the cytosol. In yeast, it is formed by the AAA ATPase Vps4 and its cofactor Vta1.


ISWI-type complex

Any nuclear protein complex that contains an ATPase subunit of the imitation switch (ISWI) family. ISWI ATPases are involved in assembling chromatin and in sliding and spacing nucleosomes to regulate transcription of nuclear RNA polymerases I, II, and III and also DNA replication, recombination and repair.


GBAF complex

A SWI/SNF subcomplex that incorporates two mutually exclusive paralogs, GLTSCR1 (glioma tumor suppressor candidate region gene 1) or GLTSCR1L (GLTSCR1-like), BRD9 (bromodomain-containing 9) and the BAF subunits BAF155, BAF60, SS18, BAF53a, and BRG1/BRM.


chloroplast proton-transporting ATP synthase complex

A proton-transporting ATP synthase complex found in the chloroplast thylakoid membrane; it catalyzes the phosphorylation of ADP to ATP during photo-phosphorylation.


NURF complex

An ISWI complex that contains an ATPase subunit of the ISWI family (SNF2L in mammals), a NURF301 homolog (BPTF in humans), and additional subunits, though the composition of these additional subunits varies slightly with species. NURF is involved in regulation of transcription from TRNA polymerase II promoters.


CHD-type complex

A SWI/SNF-type complex that contains a subunit from the CHD(Chromodomain helicase DNA-binding) family. The CHD family is characterized by two signature sequence motifs: tandem chromodomains located in the N-terminal region, and the SNF2-like ATPase domain located in the central region of the protein structure.


NuRD complex

An approximately 2 MDa multi-subunit complex that exhibits ATP-dependent chromatin remodeling activity in addition to histone deacetylase (HDAC) activity, and has been shown to establish transcriptional repression of a number of target genes in vertebrates, invertebrates and fungi. Amongst its subunits, the NuRD complex contains histone deacetylases, histone binding proteins and Mi-2-like proteins.


CHRAC

An ISWI complex that contains an ATPase subunit of the ISWI family (SNF2H in mammals, Isw2 in S. cerevisiae), an ACF1 homolog, and additional small histone fold subunits (generally two of these, but Xenopus has only one and some additional non-conserved subunits). CHRAC plays roles in the regulation of RNA polymerase II transcription and in DNA replication and repair.


enhanceosome

A protein-DNA complex formed by the association of a distinct set of general and specific transcription factors with a region of enhancer DNA. The cooperative assembly of an enhanceosome confers specificity of transcriptional regulation.


Cdc42 GTPase complex

A protein complex formed by the association of the small GTPase Cdc42 with additional proteins. In Schizosaccharomyces the complex contains the Cdc42, Ras1, Scd1, Scd2, andShk1 proteins, and functions in the Ras1-Scd GTPase signaling pathway.


Derlin-1 retrotranslocation complex

A protein complex that functions in the retrotranslocation step of ERAD (ER-associated protein degradation), and includes at its core Derlin-1 oligomers forming a retrotranslocation channel.


lateral wall of outer hair cell

The lateral wall of an outer hair cell (OHC) is a unique trilaminate composite consisting of the plasma membrane, an underlying cytoskeletal network containing an actin-spectrin cortical lattice, and an adjacent system of circumferential lamellar organelles known as the subsurface cisternae.


pathogen-containing vacuole

A membrane-bound intracellular compartment that is formed upon internalization of a pathogen into a host cell, and in which the pathogen resides.


IRE1-RACK1-PP2A complex

A protein complex consisting of IRE1 (Inositol-requiring enzyme-1), RACK1 (Receptor of activated protein kinase C 1, GNB2L1) and PP2A (protein phosphatase 2A). RACK1 acts as an adaptor to bridge an interaction between IRE1 and PP2A.


non-canonical inflammasome complex

An inflammasome complex containing CASP4, known as caspase-11 (Casp11) in mouse, which assembles upon cytosolic lipopolysaccharide-binding and directly activates Gasdermin-D (GSDMD).


type III site-specific deoxyribonuclease complex

A heterodimeric enzyme complex composed of two subunits, Res and Mod, that functions as an endonuclease and cleaves DNA. Cleavage will only occur when there are two un-methylated copies of a specific recognition site in an inverse orientation on the DNA. Cleavage occurs at a specific distance away from one of the recognition sites. The Mod subunit can act alone as a methyltansferase. DNA restriction systems such as this are used by bacteria to defend against phage and other foreign DNA that may enter a cell.


A heterodimeric complex between the tyrosine kinase receptor ERBB2 and a ligand-activated epidermal growth factor receptor (EGFR/ERBB1). ERBB2, which does not bind any known ligand, is activated through formation of a heterodimer with another ligand-activated ERBB family member such as EGFR.


Holliday junction resolvase complex

An endodeoxyribonuclease complex that resolves the 4-way DNA intermediates of a Holliday junction into two separate duplex DNA molecules. Can be branch-migration associated.


glial cell projection

A prolongation or process extending from a glial cell.


astrocyte end-foot

Terminal process of astrocyte abutting non-neuronal surfaces in the brain.


spiny bracelet of Nageotte

Paranodal terminations of Schwann cells that do not directly contact the paranodal axon membrane. Usually found in thicker myelin.


astrocyte projection

A prolongation or process extending from the soma of an astrocyte and wrapping around neurons.


glial limiting end-foot

Terminal process of astrocyte that extends to the surface of the central nervous system. Together, glial limiting end-feet form the glial limiting membrane or glia limitans.


terminal loop

Portion of myelin-forming Schwann cell consisting of terminal cytoplasmic extensions adhered to the axon at the beginning and end of the myelin sheath.


capitate projection

Simple or compound process of epithelial glial cells with a spherical head that inserts into photoreceptor axons. Capitate projections have only been observed in Brachycera (flies).


ankyrin-1 complex

A complex composed of ANK1, RHCE, RHAG, SLC4A1, EPB42, GYPA, GYPB and AQP1, that functions in the stability and shape of the erythrocyte membrane in human.


cerebellar granule cell to Purkinje cell synapse

A synapse of a granule cell fiber onto the dendrites of a Purkinje cell in cerebellum.


pre-T cell receptor complex

A receptor complex found on immature T cells consisting of a T cell receptor beta chain and the pre-TCR-alpha chain, along with additional signaling components including CD3 family members and additional signaling proteins.


dense nuclear body

A location in the host cell nucleus where viral proteins colocalize late in infection prior to the onset of viral DNA synthesis. More than one site can be present simultaneously.


HSP90-CDC37 chaperone complex

A protein kinase chaperone complex required for the proper folding, maturation and stabilization of target proteins (mostly signaling protein kinases, some steroid hormone receptors), usually during or immediately after completion of translation. The highly conserved, phosphorylated CDC37-Ser13 (vertebrates) or cdc37-Ser14 (yeast) is essential for complex assembly and target protein binding. CDC37-Ser13 (Ser14) is phosphorylated by Casein kinase II (CK2), which in turn is a target of CDC37 creating a positive feedback loop. Complex binding also prevents rapid ubiquitin-dependent proteosomal degradation of target proteins.


NuA3 histone acetyltransferase complex

A Gcn5-independent multisubunit complex that catalyzes the acetylation of histone H3. The budding yeast complex includes Sas3p, Taf30p, and Yng1p.


NatA complex

A conserved complex that catalyzes the transfer of an acetyl group to an N-terminal Ser, Ala, Gly, or Thr residue of a protein acceptor molecule. In Saccharomyces the complex includes Nat1p and Ard1p, and may contain additional proteins.


Mst2 histone acetyltransferase complex

A protein complex that can catalyze the acetylation of lysine at position 14 in histone H3, and contains Mst2 as the catalytic subunit. In fission yeast, contains at least Mst2, Nto1, Ptf2, Ptf1 and Eaf6.


transcription factor TFTC complex

A protein complex that does not contain either a TATA-binding protein (TBP) or a TBP-like factor, but is composed of several TAFIIs and other proteins, including a histone acetyltransferase. This complex is able to nucleate transcription initiation by RNA polymerase II, can mediate transcriptional activation, and has histone acetyltransferase activity.


histone H3-K14 acetyltransferase complex

A protein complex that can catalyze the acetylation of lysine at position 14 in histone H3.


Hpa2 acetyltransferase complex

A tetrameric protein complex capable of acetyltransferase activity. It can catalyze the transfer of an acetyl group from acetyl-CoA to an acceptor residue on histone H-3, histone H-4, or on polyamines. The complex is also capable of acetylating certain small basic proteins. The two Hpa2 dimers that make up the tetramer are held together by interactions between the bound acetyl-CoA molecules.


NuA3a histone acetyltransferase complex

A NuA3 complex that catalyzes the acetylation of Histone H3. In S. cerevisiae, this complex consists of Eaf6p, Nto1p, Sas3p, Taf14p, Yng1p and associates with H3K4me3 using Yng1p.


NatC complex

A conserved complex that catalyzes the transfer of an acetyl group to the N-terminal residue of a protein acceptor molecule that has a Met-Ile, Met-Leu, Met-Trp, or Met-Phe N-terminus. In Saccharomyces the complex includes Mak3p, Mak10p, and Mak31p.


MOZ/MORF histone acetyltransferase complex

A histone acetyltransferase complex that has histone H3 acetyltransferase and coactivator activities. Subunits of the human complex include MYST3/MOZ, MYST4/MORF, ING5, EAF6 and one of BRPF1, BRD1/BRPF2 and BRPF3.


NSL complex

A histone acetyltransferase complex that catalyzes the acetylation of a histone H4 lysine residues at several positions. In human, it contains the catalytic subunit MOF, NSL1/KIAA1267, NSL2/KANSL2, NSL3/KANSL3, MCRS1, PHF20, OGT1, WDR5 and HCF1.


ATAC complex

A chromatin remodeling complex that regulates transcription via acetylation primarily of nucleosomal histones H3 and possibly H4. Shares the histone acetylation (HAT) module of GCN5/PCAF-ADA2-ADA3-SGF29 (or orthologs) with the related SAGA complex (GO:0000124). Contains HAT subunits GCN5 or PCAF in a mutually exclusive manner. In addition to the HAT module contains DR1/NC2B, KAT14, MBIP, WDR5, YEATS2 and ZZZ3 or orthologs. Also regulates the activity of non-histone targets and orchestrates mitotic progression by regulating Cyclin A degradation through acetylation.


H3 histone acetyltransferase complex

A multisubunit complex that catalyzes the acetylation of histone H3.


diamine N-acetyltransferase complex

A protein complex which is capable of diamine N-acetyltransferase activity.


N-terminal protein acetyltransferase complex

A complex that catalyzes the transfer of an acetyl group to the N-terminal residue of a protein acceptor molecule.


MSL complex

A histone acetyltransferase complex that catalyzes the acetylation of a histone H4 lysine residue at position 16. In human, it contains the catalytic subunit MOF, and MSL1, MSL2 and MSL3.


ADA complex

A chromatin remodeling complex that regulates transcription via acetylation primarily of nucleosomal histones H3 and H2B. In budding yeast shares the histone acetylation (HAT) module of ADA2-GCN5-NGG1-SGF29 with the related SAGA complex.


H4 histone acetyltransferase complex

A protein complex which is capable of H4 histone acetyltransferase activity.


NAGS/NAGK complex

A protein complex that acts both as N-acetylglutamate synthase (NAGS) catalysing the production of N-Acetylglutamate from glutamate and acetyl-CoA, and as N-acetylglutamate kinase (NAGK) catalysing the reaction ATP + N-acetyl-L-glutamate = ADP + N-acetyl-L-glutamyl 5-phosphate.


H4/H2A histone acetyltransferase complex

A multisubunit complex that catalyzes the acetylation of histones H4 and H2A.


SLIK (SAGA-like) complex

A SAGA-type histone acetyltransferase complex that contains a smaller form of Spt7 (lacking the SPT8 binding region) than the fungal SAGA complex, and consequently lacks Spt8. The complex is involved in the yeast retrograde response pathway, which is important for gene expression changes during mitochondrial dysfunction.


NuA3b histone acetyltransferase complex

A NuA3 complex that catalyzes the acetylation of Histone H3. In S. cerevisiae, this complex consists of Eaf6p, Nto1p, Sas3p, Taf14p, Pdp3 and associates with H3K4me3 via Pdp3p.


EGFR-Grb2-Sos complex

A protein complex that contains the epidermal growth factor receptor (EGFR), Grb2 and the guanine nucleotide exchange factor Sos (or an ortholog thereof, such as mSos1), and is involved in linking EGFR activation to the p21-Ras pathway.


dystroglycan complex

A protein complex that includes alpha- and beta-dystroglycan, which are alternative products of the same gene; the laminin-binding component of the dystrophin-associated glycoprotein complex, providing a link between the subsarcolemmal cytoskeleton (in muscle cells) and the extracellular matrix. Alpha-dystroglycan is an extracellular protein binding to alpha-laminin and to beta-dystroglycan; beta-dystroglycan is a transmembrane protein which binds alpha-dystroglycan and dystrophin.


ventral disc microtubule array

A part of the ventral disc of Giardia species (trophozoite stage) consisting of a spiral array of microtubules linked to the ventral membrane. These microtubules form the base of the ventral disc dorsal microribbons that extend nearly perpendicular from the membrane.


chloroplast intermembrane space

The region between the inner and outer lipid bilayers of a chloroplast envelope.


GATA2-TAL1-TCF3-Lmo2 complex

A protein complex that contains the zinc finger transcription factor GATA2, the LIM domain protein Lmo2 (RBTN2), the basic helix-loop-helix protein TAL1 and its binding partner TCF3. The complex is involved transcriptional regulation in hematopoiesis.


Flemming body

A cell part that is the central region of the midbody characterized by a gap in alpha-tubulin staining. It is a dense structure of antiparallel microtubules from the central spindle in the middle of the intercellular bridge.


viral scaffold

A complex of proteins that form a scaffold around which the viral capsid is constructed.


unencapsulated part of cell

The part of a cell encompassing the intracellular environment and the plasma membrane; it excludes any external encapsulating structures.


glyoxysomal lumen

The volume enclosed by the membranes of a glyoxysome.


glycosome lumen

The volume enclosed by the membrane of a glycosome.


cytosolic proteasome core complex, alpha-subunit complex

The proteasome core subcomplex that constitutes the two outer rings of the cytosolic proteasome core complex.


lateral part of cell

The region of a polarized cell other than its tips or ends (in some cell types, one end may be called the apex and the other the base). For example, in a polarized epithelial cell, the lateral part includes the cell sides which interface adjacent cells.


lateral part of motile cell

The area of a motile cell perpendicular to the direction of movement.


incipient cellular bud site

The portion of the budding yeast plasma membrane where a daughter cell will emerge. The yeast marks this spot with bud-site selection proteins before bud emergence occurs. Actin is polarized to this spot just prior to and during bud emergence.


meiotic cohesin complex

A cohesin complex that mediates sister chromatid cohesion during meiosis; has a subunit composition distinct from that of the mitotic cohesin complex.


cohesin complex

A protein complex that is required for sister chromatid cohesion in eukaryotes. The cohesin complex forms a molecular ring complex, and is composed of structural maintenance of chromosomes (SMC) and kleisin proteins. For example, in yeast, the complex is composed of the SMC proteins Smc1p and Smc3p, and the kleisin protein Scc1p. In vertebrates, the complex is composed of the SMC1 (SMC1A or SMC1B) and SMC3 heterodimer attached via their hinge domains to a kleisin (RAD21, REC8 or RAD21L) which links them, and one STAG protein (STAG1, STAG2 or STAG3).


mitotic cohesin complex

A cohesin complex that mediates sister chromatid cohesion during mitosis; has a subunit composition distinct from that of the meiotic cohesin complex.


ethanolamine degradation polyhedral organelle

An organelle found in bacteria consisting of a proteinaceous coat containing enzymes for the degradation of ethanolamine whose purpose is the protection of the rest of the cell from the toxic acetaldehyde product of the enzyme ethanolamine ammonia lyase.


Derlin-1-VIMP complex

A protein complex containing, in mammals, Derlin-1 and VCP-interacting membrane protein (VIMP). The complex links the p97/VCP-containing ATPase complex with Derlin-1 during translocation of protein substrates from the endoplasmic reticulum to the cytosol for degradation by the cytosolic proteasome.


ESCRT II complex

An endosomal sorting complex required for transport and functions downstream of ESCRT I complex. It consists of the class E vacuolar protein sorting (Vps) proteins and is required for the membrane recruitment of ESCRT III complex and binds to ubiquitinated cargoes.


Ubisch body

A small, granular structure that is found in the extracellular matrix of cell of the secretory tapetal layer that surrounds developing pollen grains. Ubisch bodies have a sporopollenin coat, are attached to the peritapetal wall, and may play a role in pollen development.


SCF-Saf1/Pof9 ubiquitin ligase complex

An SCF ubiquitin ligase complex in which the F-box protein is Saf1 in S. cerevisiae (Pof9 in S. pombe).


cytoplasmic microtubule plus-end

Any microtubule plus-end that is part of a cytoplasmic microtubule.


cortical microtubule plus-end

The plus-end of a cortical microtubule.


neutrophil extracellular trap

Extracellular microbicidal structure composed of nuclear chromatin, histones and granular antimicrobial proteins. Histones and several neutrophil granule proteins associated with the DNA framework damage entrapped microorganisms.


alphaIIb-beta3 integrin-talin complex

A protein complex that consists of an alphaIIb-beta3 integrin complex bound to talin.


U4/U6 snRNP

A ribonucleoprotein complex that contains the extensively base paired small nuclear RNAs U4 and U6, a heptameric ring of Sm proteins associated with U4, the Lsm2-8 heptameric ring complex associated with U6, as well as several proteins that are unique to the U4 snRNP or U6 snRNPs, some of which remain associated with the U4/U6 snRNA both while the U4 snRNP is free or assembled into a series of spliceosomal complexes.


host cell chloroplast

A chlorophyll-containing plastid as found within host cells with thylakoids organized into grana and frets, or stroma thylakoids, and embedded in a stroma. The host is defined as the larger of the organisms involved in a symbiotic interaction.


host cell chloroplast thylakoid membrane

Any sac-like membranous structures (cisternae) in a chloroplast found in host cells, combined into stacks (grana) and present singly in the stroma (stroma thylakoids or frets) as interconnections between grana. The host is defined as the larger of the organisms involved in a symbiotic interaction.


host cell chloroplast part

Any constituent part of a chloroplast as it is found in host cells and which are a chlorophyll-containing plastid with thylakoids organized into grana and frets, or stroma thylakoids, and embedded in a stroma. The host is defined as the larger of the organisms involved in a symbiotic interaction.


excitatory neuromuscular junction of somatic myotube

A neuromuscular junction that functions in the excitation of somatic muscle myotubes, such as an arthropod somatic muscle cells.


inhibitory neuromuscular junction

The junction between the axon of a motor neuron and a muscle fiber. In response to the arrival of action potentials, the presynaptic button releases molecules of neurotransmitters into the synaptic cleft. These diffuse across the cleft and transmit the signal to the postsynaptic membrane of the muscle fiber, leading to a change in post-synaptic potential that inhibits muscle contraction.


inhibitory neuromuscular junction of somatic myotube

A neuromuscular junction that functions in the inhibition of somatic muscle myotube contraction. Examples of somatic muscle myotubes include the somatic muscle cells of arthropods.


neuromuscular junction of myotube

A neuromuscular junction in which the target muscle cell is a myotube.


neuromuscular junction of somatic muscle

A neuromuscular junction in which the target muscle cell is a somatic muscle cell, such as those found in nematodes and arthropods.


neuromuscular junction of somatic muscle myotube

A neuromuscular junction in which the target muscle cell is a somatic muscle myotube, such as an arthropod somatic muscle cell.


excitatory neuromuscular junction

The junction between the axon of a motor neuron and a muscle fiber. In response to the arrival of action potentials, the presynaptic button releases molecules of neurotransmitters into the synaptic cleft. These diffuse across the cleft and transmit the signal to the postsynaptic membrane of the muscle fiber, leading to a post-synaptic potential responsible for muscle contraction.


smooth endoplasmic reticulum membrane

The lipid bilayer surrounding the smooth endoplasmic reticulum.


excitatory synapse

A synapse in which an action potential in the presynaptic cell increases the probability of an action potential occurring in the postsynaptic cell.


parallel fiber to Purkinje cell synapse

An excitatory synapse formed by the parallel fibers of granule cells synapsing onto the dendrites of Purkinje cells.


cerebellar climbing fiber to Purkinje cell synapse

A synapse of a climbing fiber onto the dendrites of a Purkinje cell in cerebellum. The climbing fiber originates from the inferior olivary nucleus of the medulla oblongata.


asymmetric, glutamatergic, excitatory synapse

A neuron to neuron synapse with a postsynaptic density, that uses glutamate as a neurotransmitter and whose activity results in excitatory postsynaptic potentials.


P1 peroxisome

A subform of peroxisome that corresponds to an intermediate in a peroxisome assembly pathway, which operates by conversion of peroxisomal subforms in the direction P1, P2 -> P3 -> P4 -> P5 -> P6. P1 peroxisomes are distinguished from the other subforms on the bases of buoyant density and protein content; they contain fewer peroxisomal proteins than the other subforms.


bursicon neuropeptide hormone complex

A neuropeptide hormone secreted by the central nervous system of insects that stimulates the tanning and sclerotization of the adult cuticle following eclosion. The active hormone consists of an obligate heterodimer of the alpha and beta subunits.


nucleotide-excision repair factor 1 complex

One of several protein complexes involved in nucleotide-excision repair; possesses DNA damage recognition and endodeoxynuclease activities. In S. cerevisiae, it is composed of Rad1p, Rad10p, and Rad14p; in human the subunits are ERCC4/XPF, ERCC1 and XPA, respectively.


phosphatidylinositol 3-kinase complex, class IA

A class I phosphatidylinositol 3-kinase complex that possesses 1-phosphatidylinositol-4-phosphate 3-kinase activity; comprises a catalytic class IA phosphoinositide 3-kinase (PI3K) subunit and an associated SH2 domain-containing regulatory subunit that is a member of a family of related proteins often called p85 proteins. Through the interaction with the SH2-containing adaptor subunits, Class IA PI3K catalytic subunits are linked to tyrosine kinase signaling pathways.