Plays a role in fertilization by controlling binding of sperm to zona pellucida and migration of spermatozoa into the oviduct (By similarity). May play a role in signal transduction and promote protein tyrosine phosphorylation (PubMed:11809740). Interacts with VAMP3. Interacts with LY6K. Interacts with DPEP3; co-localized on the cell surface of spermatocytes, spermatids, and testicular spermatozoa, co-localized only in cytoplasmic droplets of caput and corpus epididymal sperm. Interacts with ADAM5. Located on plasma membrane of spermatocytes, round and elongated spermatids, and testicular spermatozoa. Detected in testis. N-glycosylated; by high mannose and/or biantennary complex and/or certain types of hybrid oligosaccharides; possesses different oligosaccharides chains according to its subcellular localization in the testis. Sheds from membrane raft by ACE and released from the cell surface of epididymal sperm while it passes through the caput epididymis leading to disappearance of TEX101 on spermatozoa; is essential to produce fertile spermatozoa.