Protein Tyrosine Phosphatase, Mitochondrial 1 (PTPMT1)

PTPMT1 is a recently discovered dual specificity phosphatase that has been implicated in the regulation of insulin secretion. Database analysis using the mouse ortholog, which encodes a deduced 261-amino acid protein, revealed 60 orthologs from 4 different phylogenetic kingdoms that share more than 70% amino acid identity within the active site region. The active site sequence between amino acids 128 and 148 of mouse and human PLIP is identical. Northern blot analysis of several mouse tissues detected highest expression in testis.Plip showed activity against PtdIns(5)P that was 44-fold greater than that against PtdIns(3,5)P2, its second most preferred substrate, when the phosphoinositides were presented in a lipid bilayer with phosphatidylserine.