InterPro: IPR016130 Protein-tyrosine phosphatase, active site

This entry includes proteins of two subfamilies: Ser/Thr (EC:3.1.3.16) and Tyr dual specificity protein phosphatase and tyrosine specific protein phosphatase (EC:3.1.3.48). Both of these subfamilies may also have inactive phosphatase domains, and dependent on the domain composition this loss of catalytic activity has different effects on protein function. Inactive single domain phosphatases can still specifically bind substrates, and protect against dephosphorylation, while the inactive domains of tandem phosphatases can be further subdivided into two classes. Those which bind phosphorylated tyrosine residues may recruit multi-phosphorylated substrates for the adjacent active domains and are more conserved, while the other class have accumulated several variable amino acid substitutions and have a complete loss of tyrosine binding capability. The second class shows a release of evolutionary constraint for the sites around the catalytic centre, which emphasises a difference in function from the first group. There is a region of higher conservation common to both classes, suggesting a regulatory centre [1].

Ser/Thr and Tyr dual specificity phosphatases are a group of enzymes with both Ser/Thr (EC:3.1.3.16) and tyrosine specific protein phosphatase (EC:3.1.3.48) activity able to remove both the serine/threonine or tyrosine-bound phosphate group from a wide range of phosphoproteins, including a number of enzymes which have been phosphorylated under the action of a kinase. Dual specificity protein phosphatases (DSPs) regulate mitogenic signal transduction and control the cell cycle. Tyrosine specific protein phosphatases catalyze the removal of a phosphate group attached to a tyrosine residue. They are also very important in the control of cell growth, proliferation, differentiation and transformation.