CATSPER (cationic channel of sperm) is a complex ion channel that mediates Ca2+ entry in sperm flagellum and is required for sperm hyperactivation and male fertility []. The CATSPER channel consists of four CatSper proteins (CatSper1-4) that form a tetramer surrounding a Ca(2+)-selective pore.In addition to the pore-forming proteins, the CATSPER channel contains auxiliary subunits []. One of these auxiliary proteins is CatSper-beta []. It is probably required for trafficking or formation of a stable channel complex.
