HGNC Approved Gene Symbol: FXYD7
Cytogenetic location: 19q13.12 Genomic coordinates (GRCh38): 19:35,143,255-35,154,302 (from NCBI)
The gene family FXYD (pronounced fix-id) consists of small membrane proteins containing a core motif of 35 invariant and conserved amino acids centered on a single transmembrane span.
By EST database searching and in silico analysis, Sweadner and Rael (2000) identified genes and protein sequences for 7 FXYD molecules in rodents and humans. The deduced FXYD7 protein contains 77 amino acids and has no signal peptide. A potential splice variant has 80 residues. Sweadner and Rael (2000) noted that ESTs for FXYD7 are restricted to the nervous system.
Using Northern and Western blot analyses of rat tissues, Beguin et al. (2002) detected a 0.7-kb Fxyd7 transcript encoding an 18-kD type I membrane protein. Expression was restricted to brain, with highest levels in cerebrum, followed by cerebellum, brainstem, and hippocampus, and relatively weak expression in hypothalamus. Immunofluorescence microscopy demonstrated colocalization with synaptophysin (SYP; 313475) and modest colocalization with glial fibrillary acidic protein (GFAP; 137780), indicating predominant expression in neurons and lower expression in astroglial cells.
Using immunoprecipitation analysis, Beguin et al. (2002) detected a preferential association of mouse Fxyd7 with alpha-1/beta-1 isozymes of Na,K-ATPase (see ATP1B1; 182310). Beguin et al. (2002) concluded that, like other members of the FXYD family, which are involved in the fine regulation of Na,K-ATPases in various tissues, FXYD7 mediates this regulation in brain.
The International Radiation Hybrid Mapping Consortium mapped the FXYD7 gene to chromosome 19.
Beguin, P., Crambert, G., Monnet-Tschudi, F., Uldry, M., Horisberger, J.-D., Garty, H., Geering, K. FXYD7 is a brain-specific regulator of Na,K-ATPase alpha-1-beta isozymes. EMBO J. 21: 3264-3273, 2002. [PubMed: 12093728] [Full Text: https://doi.org/10.1093/emboj/cdf330]
Sweadner, K. J., Rael, E. The FXYD gene family of small ion transport regulators or channels: cDNA sequence, protein signature sequence, and expression. Genomics 68: 41-56, 2000. [PubMed: 10950925] [Full Text: https://doi.org/10.1006/geno.2000.6274]