Tetraspanins
tetraspanins
Tetraspanins, also called tetraspans or the transmembrane 4 superfamily (TM4SF), have four transmembrane domains, intracellular N- and C-termini and two extracellular domains, one short (called the small extracellular domain or loop, SED/SEL or EC1) and one longer, typically 100 amino acid residues (the large extracellular domain/loop, LED/LEL or EC2).