Alternative titles; symbolsPHOSPHOLEMMAN-LIKE; PLMLMAMMARY TUMOR, 8-KD; MAT8HGNC Approved Gene Symbol: FXYD3Cytogenetic location: 19q13.12 Genomic coordinate...
Alternative titles; symbols
HGNC Approved Gene Symbol: FXYD3
Cytogenetic location: 19q13.12 Genomic coordinates (GRCh38): 19:35,115,822-35,124,323 (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.
▼ Cloning and Expression
Morrison and Leder (1994) identified a novel 8-kD transmembrane protein in mouse, designated Mat8, that was expressed in a subset of mouse breast tumors initiated by neu or ras oncogenes. Using murine Mat8 as a probe to screen a human breast cancer cDNA library, Morrison et al. (1995) isolated the human homolog of Mat8. The human MAT8 cDNA, also symbolized PLML and FXYD3, encodes a deduced 67-amino acid protein with a calculated mass of 8 kD and shows partial homology to phospholemman (PLM; 602359), a major plasmalemmal substrate for cAMP-dependent protein kinase and protein kinase C. PLML contains a putative 20-amino acid leader sequence and a putative transmembrane domain. It shares homologous extracellular and transmembrane domains with PLM, but has 2 cysteine residues in the transmembrane domain. Unlike PLM, it contains no consensus phosphorylation sites in the cytoplasmic domain. RNA blot analysis revealed expression of PLML as a major 0.5-kb transcript and minor 2.5- and 3.0-kb transcripts in all 16 primary human breast tumors and in 8 of 11 human breast carcinoma cell lines studied. Mouse Mat8 is expressed at high levels in the SMF cell line, uterus, stomach, and colon, and at lower levels in breast, ovary, lung, small intestine, and thymus. Expression of PLML in Xenopus oocytes induces hyperpolarization-activated chloride currents similar to those induced by PLM expression.
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 FXYD3 protein contains 87 amino acids. Sweadner and Rael (2000) noted that ESTs for FXYD3 are found in muscle, reproductive, and transport tissues but not in blood or nervous system tissues, suggesting wide but not ubiquitous expression.
The International Radiation Hybrid Mapping Consortium mapped the FXYD3 gene to chromosome 19 (stSG4378).