HGNC Approved Gene Symbol: INPP5A
Cytogenetic location: 10q26.3 Genomic coordinates (GRCh38): 10:132,537,787-132,783,480 (from NCBI)
The phosphatidylinositols serve as precursors for a number of different messenger molecules. Agonist stimulation of cells results in phosphatidylinositol turnover and the generation of inositol 1,4,5-triphosphate, Ins(1,4,5)P3, which mobilizes intracellular calcium. The inositol polyphosphate-5-phosphatase enzymes hydrolyze Ins(1,4,5)P3 in a signal-terminating reaction. Laxminarayan et al. (1994) isolated a 2.7-kb composite cDNA encoding the 43-kD membrane-associated 5-phosphatase by screening a human placental lambda-gt11 library using degenerate oligonucleotides. The 2.7-kb cDNA contained a 1.1-kb open reading frame, comprising 363 amino acids, which encoded a protein of predicted molecular mass of 42 kD. They showed that a 73-amino acid domain in the COOH terminus of the 43-kD membrane-associated 5-phosphatase had 30% sequence identity and 67% similarity to a region in the 75-kD 5-phosphatase (147264) and 34% identity and 70% similarity to a sequence in the protein that is encoded by the gene defective in Lowe oculocerebral renal syndrome (OCRL1; 300535). The 43-kD membrane-associated 5-phosphatase appeared to be predominantly expressed in heart, brain, and skeletal muscle.
By fluorescence in situ hybridization, Mitchell et al. (1996) mapped the INPP5A gene to 10q26.3. They gave the size of the protein as 43 kD. The 75-kD protein (147264) is encoded by a gene at 1p34. The gene that is mutated in Lowe oculocerebral renal syndrome is similar to inositol polyphosphate 5-phosphatase and maps to Xq26.1.
Laxminarayan, K. M., Chan, B. K., Tetaz, T., Bird, P. I., Mitchell, C. A. Characterization of a cDNA encoding the 43-kDa membrane-associated inositol-polyphosphate 5-phosphatase. J. Biol. Chem. 269: 17305-17310, 1994. [PubMed: 8006039]
Mitchell, C. A., Speed, C. J., Nicholl, J., Sutherland, G. R. Chromosomal mapping of the gene (INPP5A) encoding the 43-kDa membrane-associated inositol polyphosphate 5-phosphatase to 10q26.3 by fluorescence in situ hybridization. Genomics 31: 139-140, 1996. [PubMed: 8808294] [Full Text: https://doi.org/10.1006/geno.1996.0023]