Cation Channel, Sperm Associated 1 (CATSPER1)

CATSPER is a putative sperm cation channel whose amino acid sequence most closely resembles a single 6-transmembrane-spanning repeat of the voltage-dependent calcium channel 4-repeat structure. CATSPER is vital to cAMP-mediated calcium influx in sperm, sperm motility, and fertilization.

The CATSPER gene encodes a protein of 686 amino acids that is expressed exclusively in testis. Human CATSPER exhibits a high degree of homology (55% identity) with its mouse counterpart, especially in the transmembrane domains and histidine-rich region. The transmembrane domains share 81% identity and the pore regions 89% identity. current is not present in spermatozoa lacking the sperm-specific putative ion channel protein Catsper1.