Calcium ions play a primary role in the regulation of sperm motility. Anti-CATSPER2 belongs to a family of putative cation channels that are specific to spermatozoa and localize to the flagellum. The protein family features a single repeat with six membrane-spanning segments and a predicted calcium-selective pore region. A second, closely linked copy of this gene has been identified. Although multiple transcript variants encoding protein isoforms have been characterized, they seem to be only transcribed from this gene. Additional splice variants have been described but their full-length nature has not been determined.