CatSper3, is a protein which in humans is encoded by the CATSPER3 gene.    CatSper3 is a member of the  cation channels of sperm family of proteins. The four proteins in this family together form a Ca-permeant 2+ ion channel specific essential for the correct function of sperm cells.
Arias JM, Murbartián J, Perez-Reyes E (March 2003). "Cloning of a novel one-repeat calcium channel-like gene". Biochem. Biophys. Res. Commun. 303 (1): 31–6. doi: 10.1016/S0006-291X(03)00276-6. PMID 12646162.
Lobley A, Pierron V, Reynolds L, Allen L, Michalovich D (August 2003). "Identification of human and mouse CatSper3 and CatSper4 genes: Characterisation of a common interaction domain and evidence for expression in testis". Reprod. Biol. Endocrinol. 1: 53. doi: 10.1186/1477-7827-1-53. PMC . 184451 PMID 12932298.
Qi H, Moran MM, Navarro B, Chong JA, Krapivinsky G, Krapivinsky L, Kirichok Y, Ramsey IS, Quill TA, Clapham DE (January 2007). "All four CatSper ion channel proteins are required for male fertility and sperm cell hyperactivated motility". Proc. Natl. Acad. Sci. U.S.A. 104 (4): 1219–23. doi: 10.1073/pnas.0610286104. PMC . 1770895 PMID 17227845.
Clapham DE, Garbers DL (December 2005). "International Union of Pharmacology. L. Nomenclature and structure-function relationships of CatSper and two-pore channels". Pharmacol. Rev. 57 (4): 451–4. doi: 10.1124/pr.57.4.7. PMID 16382101.
"CatSper and Two-Pore Channels: Introduction". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology.