Transmembrane Protein 190 (TMEM190)

TMEM190, a small transmembrane protein containing the trefoil domain, The mouse Tmem190 gene exhibits testis-specific mRNA expression and that the encoded RNA is translated into a 19-kDa protein found in both testicular germ cells and cauda epididymal sperm. Mouse TMEM190 is an inner-acrosomal membrane protein of cauda epididymal sperm.TMEM190 partly relocated onto the surface of the equatorial segment, on which sperm-oocyte fusion occurs. Moreover, TMEM190 and IZUMO1, which is an immunoglobulin-like protein required for gamete fusion, co-localized in mouse sperm both before and after the acrosome reaction. However, immunoprecipitates of TMEM190 contained several sperm proteins, but did not include IZUMO1.