title: Stimulation of mitogen activated protein kinase by LDL and oxLDL in human U-937 macrophage-like cells.
abstract: Mitogen activated protein kinase in extracts of U-937 macrophage-like cells was stimulated by LDL and oxLDL. A maximum value (161% of the basal phosphotransferase activity) was obtained after 6 min exposure to oxidized LDL (27 microgram/ml) using APRTPGGRR peptide substrate. The activatory effect was more pronounced (LDL 181%, oxLDL 201%) when MAPK of stimulated cells was immunoprecipitated with anti-p42MAPK antibodies and phosphotransferase activity was assayed in immune complexes. Stimulation produced by oxLDL was inhibited by poly I, fucoidan, dextran sulfate and by the MAPKK inhibitor PD 098059 but not by PMA-mediated depletion of PKC or by pre-treatment with chloroquine or with pertussis toxin. These results suggest a direct mitogenic effect of LDL which, in the case of oxLDL, is dependent on scavenger receptor ligation but not on G-protein mediated or PKC-dependent signal transduction.
authors.affiliation: Pharmazeutisch-Chemisches Institut der Universität Heidelberg, Germany.
authors.forename: H P
authors.initials: HP
authors.lastname: Deigner
authors.forename: R
authors.initials: R
authors.lastname: Claus
mesh_terms: D000595:Amino Acid Sequence; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002460:Cell Line; D002738:Chloroquine / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D006801:Humans; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects* / Q000201:enzymology; D019950:Mitogen-Activated Protein Kinase 1; D020929:Mitogen-Activated Protein Kinase Kinases; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism; D037342:Pertussis Toxin; D010770:Phosphotransferases / Q000378:metabolism; D011069:Poly I / Q000494:pharmacology; D011134:Polysaccharides / Q000494:pharmacology; D011494:Protein Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D005419:Flavonoids; D008077:Lipoproteins, LDL; D010446:Peptide Fragments; D011134:Polysaccharides; D010566:Virulence Factors, Bordetella; C099252:oxidized low density lipoprotein; D011069:Poly I; D002738:Chloroquine; C007789:fucoidan; D037342:Pertussis Toxin; D010770:Phosphotransferases; D011494:Protein Kinases; D011505:Protein-Tyrosine Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D020929:Mitogen-Activated Protein Kinase Kinases; D013755:Tetradecanoylphorbol Acetate; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one