HGNC Approved Gene Symbol: CATSPERGCytogenetic location: 19q13.2 Genomic coordinates (GRCh38): 19:38,335,829-38,370,942 (from NCBI)▼ DescriptionCATSPER is a ...
HGNC Approved Gene Symbol: CATSPERG
Cytogenetic location: 19q13.2 Genomic coordinates (GRCh38): 19:38,335,829-38,370,942 (from NCBI)
CATSPER is a sperm-specific ion channel that mediates calcium entry into sperm and is essential for sperm hyperactivated motility and male fertility. The CATSPER complex contains 4 pore-forming subunits, CATSPER1 (606389), CATSPER2 (607249), CATSPER3 (609120), and CATSPER4 (609121), and at least 2 auxiliary proteins, CATSPERB (611169) and CATSPERG. Each pore-forming subunit has 6 transmembrane-spanning domains and an intracellular C-terminal coiled-coil domain. In addition, CATSPER1 has an intracellular N-terminal histidine-rich region. Both the pore-forming subunits and the auxiliary subunits of CATSPER localize to the sperm principal piece (review by Ren and Xia, 2010).
▼ Cloning and Expression
Using mass spectrometry and database analysis to identify peptides associated with Catsper1 in mouse sperm, followed by PCR of a testis cDNA library, Wang et al. (2009) cloned mouse Catsperg. The deduced 1,145-amino acid protein has an extracellular domain of about 1,000 amino acids, a transmembrane domain, and a short intracellular tail. Database analysis identified human CATSPERG, which shares only 55% amino acid identity with mouse Catsperg. RT-PCR of 12 mouse tissues revealed Catsperg expression in testis only. In situ hybridization localized Catsperg to spermatocytes and spermatids within seminiferous tubules. Immunofluorescence analysis detected Catsperg along the principal piece of mouse sperm.
▼ Gene Function
Wang et al. (2009) showed that Catsper1 and Catsperg coimmunoprecipitated from mouse testis; however, not all Catsperg bound to immobilized Catsper1. The amount of Catsperg protein was significantly reduced in Catsper1 -/- testis and was eliminated in Catsper1 -/- sperm. Wildtype Catsperg levels were restored by reintroduction of Catsper1 expression in Catsper1 -/- mice. Wang et al. (2009) hypothesized that in the absence of Catsper1, Catsperg is unstable and is degraded.
Hartz (2010) mapped the CATSPERG gene to chromosome 19q13.1 based on an alignment of the CATSPERG sequence (GenBank AL133023) with the genomic sequence (GRCh37).