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Stimulation of mitogen activated protein kinase by LDL and oxLDL in human U‐937 macrophage‐like cells
Author(s) -
Deigner Hans-Peter,
Claus Ralf
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)00371-7
Subject(s) - stimulation , protein kinase a , mitogen activated protein kinase , macrophage , mitogen activated protein kinase kinase , chemistry , microbiology and biotechnology , kinase , medicine , biochemistry , biology , in vitro
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 μ/ml) using APRTPGGRR peptide substrate. The activatory effect was more pronounced (LDL 181%, oxLDL 201%) when MAPK of stimulated cells was immunoprecipitated with anti‐p42 MAPK 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.