Protein tyrosine phosphatase-like domains of phytases and similar domains
This subfamily contains the tandem protein tyrosine phosphatase (PTP)-like domains of protein tyrosine phosphatase-like phytases (PTPLPs) and similar domains including the PTP domain of Pseudomonas syringae tyrosine-protein phosphatase hopPtoD2. PTPLPs, also known as cysteine phytases, are one of four known classes of phytases, enzymes that degrade phytate (inositol hexakisphosphate [InsP(6)]) to less-phosphorylated myo-inositol derivatives. Phytate is the most abundant cellular inositol phosphate and plays important roles in a broad scope of cellular processes, including DNA repair, RNA processing and export, development, apoptosis, and pathogenicity. PTPLPs adopt a PTP fold, including the active-site signature sequence (CX5R(S/T)) and utilize a classical PTP reaction mechanism. However, these enzymes display no catalytic activity against classical PTP substrates due to several unique structural features that confer specificity for myo-inositol polyphosphates.