Cation Channel, Sperm Associated Gamma (CATSPERg)

CATSPERG is a subunit of the CATSPER sperm calcium channel, which is required for sperm hyperactivated motility and male fertility.The deduced 1,145-amino acid protein has an extracellular domain of about 1,000 amino acids, a transmembrane domain, and a short intracellular tail. Database analysis identified human CATSPERG, which shares only 55% amino acid identity with mouse Catsperg. RT-PCR of 12 mouse tissues revealed Catsperg expression in testis only. In situ hybridization localized Catsperg to spermatocytes and spermatids within seminiferous tubules. Immunofluorescence analysis detected Catsperg along the principal piece of mouse sperm.Catsper1 and Catsperg coimmunoprecipitated from mouse testis; however, not all Catsperg bound to immobilized Catsper1.