PHPT1

PHPT1,also known as 14 kDa phosphohistidine phosphatase, phosphohistidine phosphatase1, protein janus-A homolog, PHP14, is a cytoplasm protein which belongs tothe janus family. PHPT1 / PHP14 is expressed abundantly in heart andskeletal muscle. Phosphatases are a diverse group of enzymes that regulatenumerous cellular processes. Much of what is known relates to the tyrosine,threonine, and serine phosphatases, whereas the histidine phosphatases have notbeen studied as much. Protein histidine phosphorylation exists widely invertebrates, and it plays important roles in signal transduction and othercellular functions. Protein histidine phosphorylation accounts for about 6% ofthe total protein phosphorylation in eukaryotic cells. The knowledge abouteukaryotic PHPT (protein histidine phosphatase) is still very limited. To date,only one vertebrate PHPT has been discovered, and two crystal structures ofhuman PHPT1 have been solved. PHPT1 / PHP14 can dephosphorylate a variety ofproteins (e.g. ATP-citrate lyase and the beta-subunit of G proteins). Aputative active site has been identified by its electrostatic character, ionbinding, and conserved protein residues.