Sperm-specific cation channel: CatSper

Abstract

The sperm-specific cation channel (CatSper) is an essential calcium-conducting channel responsible for regulating hyperactivated motility and promoting sperm fertility. Located on the sperm flagellum, CatSper is regulated by alkalinization, voltage, and various molecules present in the female reproductive tract. CatSper forms a tetrameric complex composed of pore-forming proteins, six auxiliary subunits, and three additional proteins: C2CD6, SLCO6C1, and TEM249. The removal of any of these subunits affects male fertility due to the absence or reduced activity of the channel. The inability to express this ion channel in heterologous systems has hindered a complete understanding of its function and regulation. However, various techniques and bioinformatic tools have allowed for the study of the function and conservation of the channel across different groups within the animal kingdom. These studies suggest that the phylogenetic distribution of CatSper may represent an adaptation of its subunits, enabling sperm to exhibit different physiological states for oocyte fertilization. This review aims to analyze the structure, localization, function, activation mechanisms, and phylogenetic conservation of CatSper.