Inositol Polyphosphate-4-Phosphatase Type I 107kDa (INPP4A)

INPP4A encodes the inositol polyphosphate 4-phosphatase type I, one of the enzymes involved in phosphatidylinositol signaling pathways. This enzyme removes the phosphate group at position 4 of the inositol ring from inositol 3,4-bisphosphate.A PCR product was obtained and used to isolate a 5,607-bp composite cDNA which encodes a 939-amino acid reading frame from the rat. The authors screened a human brain cDNA library and identified a sequence that predicts a 938-amino acid protein which is 97% identical to the rat protein. Recombinant protein was shown to have the appropriate enzymatic activity. In the rat, the gene is widely expressed with highest levels in the brain, heart, and skeletal muscle.