title: Co-purification of mitogen-activated protein kinases with phorbol ester-induced c-Jun kinase activity in U937 leukaemic cells.
abstract: Phorbol esters, such as phorbol myristate acetate (PMA), cause differentiation of U937 human monomyelocytic cells along the macrophage pathway. Within 15 min of PMA treatment DNA binding of the c-jun transcription factor is increased and is accompanied by rapid changes in the phosphate content of the c-jun protein. Phorbol esters stimulate phosphorylation of serines 63 and 73 located within the A1 transactivation domain of c-Jun that have previously been shown to positively regulate activity. A protein kinase activity is detectable in extracts of phorbol ester-treated U937 cells that specifically targets these two serines. Using novel assays, the protein kinase activity has been purified over 1000-fold. The major portion of protein kinase activity co-chromatographs over three columns with pp42/44 mitogen-activated protein kinases as judged by immunological methods. The significance of these results with respect to mitogen-induced transcription of AP-1-responsive genes is discussed.
authors.affiliation: Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Canada.
authors.forename: B J
authors.initials: BJ
authors.lastname: Pulverer
authors.forename: K
authors.initials: K
authors.lastname: Hughes
authors.forename: C C
authors.initials: CC
authors.lastname: Franklin
authors.forename: A S
authors.initials: AS
authors.lastname: Kraft
authors.forename: S J
authors.initials: SJ
authors.lastname: Leevers
authors.forename: J R
authors.initials: JR
authors.lastname: Woodgett
mesh_terms: D001483:Base Sequence; D006801:Humans; D007951:Leukemia, Myeloid / Q000201:enzymology*; D019950:Mitogen-Activated Protein Kinase 1; D008969:Molecular Sequence Data; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000302:isolation & purification*; D011505:Protein-Tyrosine Kinases / Q000302:isolation & purification*; D016755:Proto-Oncogene Proteins c-jun / Q000302:isolation & purification*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: D016755:Proto-Oncogene Proteins c-jun; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D019950:Mitogen-Activated Protein Kinase 1; D013755:Tetradecanoylphorbol Acetate