This entry includes proteins from chordates that contain a UPAR/Ly6 domain, including Sperm acrosome membrane-associated protein 4 (SPACA4) from humans and Protein Bouncer (Bncr) from Danio rerio (Zebrafish). SPACA4 (also known as Sperm acrosomal membrane-associated protein 14) is a sperm surface membrane protein that may be involved in sperm-egg plasma membrane adhesion and fusion during fertilization [].Bncr is an oocyte-expressed fertilization factor that mediates sperm-egg binding and is essential for sperm entry into the egg and to mediate species-specific gamete recognition and fertilization, which is vital for vertebrate species performing external fertilization [].
