title: Dual phosphorylation and autophosphorylation in mitogen-activated protein (MAP) kinase activation.
abstract: p42mapk [mitogen activated protein (MAP) kinase; extracellular signal-regulated protein kinase (ERK)] is a serine/threonine-specific protein kinase that is activated by dual tyrosine and threonine phosphorylation in response to diverse agonists. Both the tyrosine and threonine phosphorylations are necessary for full enzymic activity. A MAP kinase activator recently purified and cloned has been shown to be a protein kinase (MAP kinase kinase) that is able to induce the dual phosphorylation of MAP kinase on both the regulatory tyrosine and threonine sites in vitro. In the present paper we have utilized MAP kinase mutants altered in the sites of regulatory phosphorylation to show, both in vivo and in vitro, that phosphorylation of the tyrosine and the threonine can occur independently of one another, with no required order of phosphorylation. We also utilized kinase-defective variants of MAP kinase with mutations in either the ATP-binding loop or the catalytic loop, and obtained data suggesting that the activity or structure of the catalytic loop of MAP kinase plays an important role in its own dual phosphorylation.
authors.affiliation: Department of Microbiology, University of Virginia, Charlottesville 22908.
authors.forename: J H
authors.initials: JH
authors.lastname: Her
authors.forename: S
authors.initials: S
authors.lastname: Lakhani
authors.forename: K
authors.initials: K
authors.lastname: Zu
authors.forename: J
authors.initials: J
authors.lastname: Vila
authors.forename: P
authors.initials: P
authors.lastname: Dent
authors.forename: T W
authors.initials: TW
authors.lastname: Sturgill
authors.forename: M J
authors.initials: MJ
authors.lastname: Weber
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D000911:Antibodies, Monoclonal; D001483:Base Sequence; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000096:biosynthesis / Q000378:metabolism*; D004789:Enzyme Activation; D000939:Epitopes / Q000032:analysis / Q000096:biosynthesis; D007700:Kinetics; D020929:Mitogen-Activated Protein Kinase Kinases; D008969:Molecular Sequence Data; D009132:Muscles / Q000201:enzymology*; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D010455:Peptides / Q000138:chemical synthesis / Q000276:immunology; D010710:Phosphates / Q000378:metabolism; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism*; D011817:Rabbits; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism
chemical_list: D000596:Amino Acids; D000911:Antibodies, Monoclonal; D000939:Epitopes; D009838:Oligodeoxyribonucleotides; D010455:Peptides; D010710:Phosphates; D010761:Phosphorus Radioisotopes; D011994:Recombinant Proteins; D011494:Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D020929:Mitogen-Activated Protein Kinase Kinases