Involvement of protein kinase C and Src family tyrosine kinase in Galphaq/11-induced activation of c-Jun N-terminal kinase and p38 mitogen-activated protein kinase.
Mitogen-activated protein kinases (MAPKs) are activated by various extracellular stimuli. The signaling pathways from G protein-coupled receptors to extracellular signal-regulated kinase have been partially elucidated, whereas the mechanisms by which G protein-coupled receptors stimulate c-Jun N-terminal kinase (JNK) and p38 MAPK activities remain largely unknown. We have recently demonstrated that the signal from Gq/11-coupled m1 muscarinic acetylcholine receptor to p38 MAPK is mediated by both Galphaq/11 and Gbeta gamma in HEK-293 cells (Yamauchi, J., Nagao, M., Kaziro, Y., and Itoh, H. (1997) J. Biol. Chem. 272, 27771-27777). In the present study, we report that a constitutively activated mutant of Galpha11 (Galpha11 Q209L) activated not only p38 MAPK, but also JNK, and the activation of JNK and p38 MAPK by Galpha11 Q209L was partially inhibited by prolonged treatment with phorbol 12-myristate 13-acetate and calphostin C. In addition, the Galpha11 Q209L-stimulated activation of both kinases was blocked by a specific inhibitor of protein tyrosine kinases (PP2) and Csk (C-terminal Src kinase). Furthermore, we demonstrated that Galpha11 Q209L stimulated Src family kinase activity and induced tyrosine phosphorylation of several proteins in HEK-293 cells. These results suggest that Galphaq/11 stimulates JNK and p38 MAPK activities through protein kinase C- and Src family kinase-dependent signaling pathways.
Nagao
M
M
Faculty of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
Yamauchi
J
J
Kaziro
Y
Y
Itoh
H
H
D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D009154:Mutation; D009281:Naphthalenes / Q000494:pharmacology; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D015398:Signal Transduction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases; D018631:ras Proteins / Q000235:genetics; D019061:src-Family Kinases / Q000378:metabolism*
D009281:Naphthalenes; D011505:Protein-Tyrosine Kinases; D019061:src-Family Kinases; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D019204:GTP-Binding Proteins; D018631:ras Proteins; C058819:calphostin C; D013755:Tetradecanoylphorbol Acetate