The function of this family of transmembrane proteins, CATSPERB, has not, as yet, been determined. However, it is thought to play a role in sperm hyperactivation by associating with CATSPER1 [1]. This family of proteins is found in eukaryotes. Proteins in this family are typically between 220 and 1107 amino acids in length.

1: CatSperbeta, a novel transmembrane protein in the CatSper channel complex. Liu J, Xia J, Cho KH, Clapham DE, Ren D; J Biol Chem. 2007;282:18945-18952. PMID:17478420