Inositol Polyphosphate-5-Phosphatase 40kDa (INPP5A)

INPP5A is a membrane-associated type I inositol 1,4,5-trisphosphate (InsP3) 5-phosphatase. InsP3 5-phosphatases hydrolyze Ins(1,4,5)P3, which mobilizes intracellular calcium and acts as a second messenger mediating cell responses to various stimulation.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 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).