CatSpermasome complex
catspermasome complex
Sperm-specific cation channel, CatSper mediated Ca2+ signalling initiates the tyrosine phosphorylation cascade thereby controlling sperm motility. Also plays a central role in sperm chemotaxis, and mediates the Ca2+ influx induced by the steroid sex hormone progesterone in human sperm. Defective CatSper function affects migration, possibly preventing sperm reaching the site of fertilization, thereby displaying an infertility phenotype in mice and humans. Deletions of CatSper2 and CatSper epsilon variants c.2394_2399del are associated with CatSper-related male infertility. Complex contains the largest number of subunits of any known ion channel with CatSper1-4 conforming to the canonical domain-swapped voltage-gated ion channel fold in a counterclockwise direction, while the auxiliary subunits CatSper-beta, gamma, delta and epsilon exist in a pavilion-like structure that stabilizes the entire complex through interactions with CatSper4, 1, 3 and 2 respectively.