Protein tyrosine phosphatase (PTP)

In vivo, tyrosine phosphorylation is reversible and dynamic; the phosphorylation states are governed by the opposing activites of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). PTPs are involved in controlling of diverse array of cellular process. They are large(~100) and structurally diverse family of enzymes. PTPs contain one or two catalytic domains which is approximately 280 residues and are characterized by the existence of the signature motif HC(X)5R. The Cys and Arg residues in this motif have essential functions for catalytic activity. PTPs regulate cell growth and metabolism, with special emphasis on its ability to regulate integrin, growth factor, and cytokine signaling.