Protein tyrosine phosphatases are a group of
enzymes that remove
phosphate groups from
phosphorylated tyrosine residues on proteins. Protein tyrosine (pTyr) phosphorylation is a common post-translational modification that can create novel recognition motifs for protein interactions and cellular localization, affect protein stability, and regulate enzyme activity. As a consequence, maintaining an
appropriate level of protein tyrosine phosphorylation is essential for many cellular functions. Tyrosine-specific protein phosphatases (PTPase; ) catalyse the removal of a phosphate group attached to a tyrosine residue, using a cysteinyl-phosphate enzyme intermediate. These enzymes are key regulatory components in
signal transduction pathways (such as the
MAP kinase pathway) and
cell cycle control, and are important in the control of
cell growth,
proliferation,
differentiation,
transformation, and synaptic strengthening.