This gene encodes a member of a family of small membrane proteins that share a 35-amino acid signature sequence domain, beginning with the sequence PFXYD and containing 7 invariant and 6 highly conserved amino acids. The approved human gene nomenclature for the family is FXYD-domain containing ion transport regulator. Mouse FXYD5 has been termed RIC (Related to Ion Channel). FXYD2, also known as the gamma subunit of the Na,K-ATPase, regulates the properties of that enzyme. FXYD1 (phospholemman), FXYD2 (gamma), FXYD3 (MAT-8), FXYD4 (CHIF), and FXYD5 (RIC) have been shown to induce channel activity in experimental expression systems. Transmembrane topology has been established for two family members (FXYD1 and FXYD2), with the N-terminus extracellular and the C-terminus on the cytoplasmic side of the membrane. The protein encoded by this gene may function as a chloride channel or as a chloride channel regulator. Two transcript variants encode two different isoforms of the protein; in addition, transcripts utilizing alternative polyA signals have been described in the literature.[7]
^Sweadner KJ, Rael E (Aug 2000). "The FXYD gene family of small ion transport regulators or channels: cDNA sequence, protein signature sequence, and expression". Genomics. 68 (1): 41–56. doi:10.1006/geno.2000.6274. PMID10950925.
Grzmil M, Voigt S, Thelen P, Hemmerlein B, Helmke K, Burfeind P (Jan 2004). "Up-regulated expression of the MAT-8 gene in prostate cancer and its siRNA-mediated inhibition of expression induces a decrease in proliferation of human prostate carcinoma cells". International Journal of Oncology. 24 (1): 97–105. doi:10.3892/ijo.24.1.97. PMID14654946.
