Encoded by Protein Serine/Threonine Phosphatase Genes, Protein Serine/Threonine Phosphatases are a group of enzymes that specifically dephosphorylate phosphoserine and phosphothreonine residues in specific target proteins. Together with serine/threonine protein kinases, these enzymes regulate serine and threonine phosphorylation and dephosphorylation of target proteins in cellular signal transduction pathways typically involved in cell growth control. [ ]