CatSperbeta, a novel transmembrane protein in the CatSper channel complex

J Biol Chem. 2007 Jun 29;282(26):18945-52. doi: 10.1074/jbc.M701083200. Epub 2007 May 3.


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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Calcium Channels / genetics
  • Calcium Channels / metabolism*
  • Cell Line
  • Female
  • HSP70 Heat-Shock Proteins / metabolism
  • Humans
  • Kidney / cytology
  • Male
  • Membrane Proteins / genetics*
  • Membrane Proteins / isolation & purification
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Molecular Sequence Data
  • Multiprotein Complexes / genetics
  • Multiprotein Complexes / metabolism*
  • Patch-Clamp Techniques
  • Protein Transport / physiology
  • Sperm Tail / physiology*


  • CATSPERB protein, human
  • Calcium Channels
  • Catsper1 protein, mouse
  • Catsperb protein, mouse
  • HSP70 Heat-Shock Proteins
  • Hspa2 protein, mouse
  • Membrane Proteins
  • Multiprotein Complexes

Associated data

  • GENBANK/AK126034
  • GENBANK/EF199807