Plays a role in fertilization by controlling binding of sperm to zona pellucida and migration of spermatozoa into the oviduct probably through molecule adhesion ADAM3 (PubMed:23633567, PubMed:23969891). May play a role in signal transduction and promote protein tyrosine phosphorylation (By similarity). Interacts with VAMP3 (PubMed:16678124). Interacts with LY6K (PubMed:18503752). 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 (PubMed:21724266). Interacts with ADAM3; co-localized on sperm surface (PubMed:23633567, PubMed:23969891). Interacts with ADAM5 (PubMed:23969891). Located on plasma membrane of spermatocytes, round and elongated spermatids, and testicular spermatozoa. Detected in testis and ovary (PubMed:11207211, PubMed:15689535, PubMed:15917346, PubMed:16388701, PubMed:23969891). Expressed in spermatocytes, spermatids and testicular spermatozoa, but not in spermatogonia or interstitial cells (PubMed:18620756). Expressed abundantly in testicular germ cells (TGCs) but mostly disappeared from epididymal spermatozoa (PubMed:23633567). Detected in prospermatogonia in embryos after 14 days of development and until 8 days after birth. Not detectable in spermatogonia from over 10 day old animals. Highly expressed in spermatocytes and spermatids from 12-28 day old animals, but not in spermatogonia. Detected in embryonic ovary after 14 days of development and in newly born animals. Expression is much reduced in ovary from 4 day old animals, and not detectable thereafter. Not detectable in oocytes that are surrounded by follicular cells. 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. Knockout Tex101 mice are viable and show no overt developmental abnormalities. Males are infertile.