CatSperbeta, a novel transmembrane protein in the CatSper channel complex.
Four CatSper ion channel subunit genes (CatSpers 1-4) are required for sperm cell hyperactivation and male fertility. The four proteins assemble (presumably as a tetramer) to form a sperm-specific, alkalinization-activated Ca(2+)-selective channel. We set out to identify proteins associating with CatSper that might help explain its unique role in spermatozoa. Using a transgenic approach, a CatSper1 complex was purified from mouse testis that contained heat shock protein 70-2, a testis-specific chaperone, and CatSperbeta, a novel protein with two putative transmembrane-spanning domains. Like the CatSper ion channel subunits, CatSperbeta was restricted to testis and localized to the principal piece of the sperm tail. CatSperbeta protein is absent in CatSper1(-/-) sperm, suggesting that it is required for trafficking or formation of a stable channel complex. CatSperbeta is the first identified auxiliary protein to the CatSper channel.
Liu
Jin
J
Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Xia
Jingsheng
J
Cho
Kwang-Hyun
KH
Clapham
David E
DE
Ren
Dejian
D
D000595:Amino Acid Sequence; D000818:Animals; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D005260:Female; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D007668:Kidney / Q000166:cytology; D008297:Male; D008565:Membrane Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D021381:Protein Transport / Q000502:physiology; D013082:Sperm Tail / Q000502:physiology*
C522631:CATSPERB protein, human; D015220:Calcium Channels; C488642:Catsper1 protein, mouse; C522630:Catsperb protein, mouse; D018840:HSP70 Heat-Shock Proteins; C490434:Hspa2 protein, mouse; D008565:Membrane Proteins; D046912:Multiprotein Complexes