Cation Channel, Sperm Associated 2 (CATSPER2)

CATSPER2 is one of several sperm-specific voltage-gated ion channels that has a Ca(2+) ion-selective pore domain and a cellular localization suggesting involvement in sperm cell motility. The protein contains 6 transmembrane segments, which have characteristics of a voltage-gated ion channel, and a C-terminal cytoplasmic portion, which has possible tyrosine phosphorylation sites and an unconventional leucine zipper motif. Northern blot and PCR analyses of mouse tissues detected a 2.1-kb transcript expressed only in testis. In situ hybridization revealed Catsper2 expression limited to meiotic and postmeiotic cells. Western blot analysis showed a protein with an apparent molecular mass of 68 kD, and immunofluorescent localization showed staining of the flagellum of mouse cauda epididymal spermatozoa.