A novel, single, transmembrane protein CATSPERG is associated with CATSPER1 channel protein

Biol Reprod. 2009 Sep;81(3):539-44. doi: 10.1095/biolreprod.109.077107. Epub 2009 Jun 10.


All four CATSPER channel pore-forming subunits (CATSPER1-4) are localized in the sperm principal piece. They form an alkalization-activated Ca2+-permeable channel and are required for sperm-hyperactivated motility, egg coat penetration, and male fertility. Unlike many other ion channels, the composition of the CATSPER protein complex is poorly defined. Herein, we describe the novel protein CATSPERG associated with the CATSPER complex. CATSPERG is predicted to be a single transmembrane-spanning protein with a large extracellular domain and a short intracellular tail. Like all the CATSPERs and the previously identified CATSPER-associated protein CATSPERB, CATSPERG is only expressed in testis and is localized in the sperm principal piece. In CATSPER1-deficient sperm, the CATSPERG protein (but not the K+ channel protein KCNU1) is also lost. Together with previous findings, our data suggest that the CATSPER protein complex contains pore-forming proteins and two additional proteins (CATSPERB and CATSPERG) and that the trafficking and/or assembly of these proteins depends on CATSPER1.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Calcium Channels / metabolism*
  • Cloning, Molecular
  • Male
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics*
  • Membrane Proteins / metabolism
  • Mice
  • Mice, Transgenic
  • Models, Biological
  • Molecular Sequence Data
  • Protein Binding
  • Spermatozoa / metabolism
  • Testis / metabolism
  • Tissue Distribution


  • Calcium Channels
  • Catsper1 protein, mouse
  • Catsperg2 protein, mouse
  • Membrane Proteins