Tyrosine phosphatases in cancer: Targets for therapeutic intervention

Protein-tyrosine phosphatases (PTPases) function to remove the phosphoryl group from phosphotyrosine, phosphoserine, and phosphothreonine residues and are important regulators of cellular signal transduction. A number of enzymes from the PTPase superfamily are potential drug targets for cancer chemotherapy. Those that are discussed include: the receptor-like PTPases, PTPα, and PTPe, which dephosphorylate and activate Src; the cytoplasmic PTPase SHP-2, which is essential for growth factor-mediated signaling; JSP-1 (a.k.a. VHX, MKPX, or JKAP), which is required for the activation of growth factor and/or cytokine signaling; the PTPase that suppresses apoptosis, FAP-1; and several dual specificity phosphatases involved in the cell cycle, including Cdc25, KAP, Cdc14, and PRL.