Serine/Threonine Kinase Biology

Serine/threonine protein kinases (EC 2.7.11.1) phosphorylate the OH (hydroxyl) group on the side chain of a serine or threonine amino acid residue in a protein or polypeptide substrate with a phosphate group from ATP, producing ADP and a phosphorylated or phosphoprotein (a phosphatase does the opposite). Serine/Threonine Kinase receptors can regulate cell proliferation, programmed cell death (apoptosis), cell differentiation, and embryonic development. The specific residues to be phosphorylated are selected on the basis of the consensus sequence of residues flanking the phosphoacceptor site, and a given kinase usually phosphorylates an entire family of substrates. Types of serine/threonine kinases include MAP kinases (activated by protein phosphatases), ERK and stress-activated JNK and p38.