title: Rac and Cdc42-dependent regulation of c-Jun N-terminal kinases by the delta-opioid receptor.
abstract: Heptahelical opioid receptors utilize Gi proteins to regulate a multitude of effectors including the classical adenylyl cyclases and the more recently discovered mitogen-activated protein kinases (MAPKs). The c-Jun NH2-terminal kinases (JNKs) belong to one of three subgroups of MAPKs. In NG108-15 neuroblastoma x glioma hybrid cells that endogenously express delta-opioid receptors, delta-agonist dose-dependently stimulated JNK activity in a pertussis toxin-sensitive manner. By using COS-7 cells transiently transfected with the cDNAs of delta-opioid receptor and hemagglutinin (HA)-tagged JNK, we delineated the signaling components involved in this pathway. Sequestration of Gbetagamma subunits by transducin suppressed the opioid-induced JNK activity. The possible involvement of the small GTPases was also examined. Expression of dominant negative mutants of Rac and Cdc42 blocked the opioid-induced JNK activation, and a partial inhibition was observed in the presence of the dominant negative mutant of Ras. In contrast, the dominant negative mutant of Rho did not affect the opioid-induced JNK activation. In addition, the receptor-mediated JNK activation was dependent on Src family tyrosine kinases, but independent of phosphatidylinositol-3 kinase and EGF receptor tyrosine kinases. Collectively, these results demonstrate functional regulation of JNK by the delta-opioid receptor, and this pathway requires Gbetagamma, Src kinases and the small GTPases Rac and Cdc42.
authors.affiliation: Department of Biochemistry, the Molecular Neuroscience Center, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
authors.forename: Angel Y F
authors.initials: AY
authors.lastname: Kam
authors.forename: Anthony S L
authors.initials: AS
authors.lastname: Chan
authors.forename: Yung H
authors.initials: YH
authors.lastname: Wong
mesh_terms: D000818:Animals; D019556:COS Cells; D002460:Cell Line; D020881:Enkephalin, D-Penicillamine (2,5)- / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D019204:GTP-Binding Proteins / Q000378:metabolism; D005799:Genes, Dominant; D006822:Hybrid Cells / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D009294:Narcotics / Q000494:pharmacology; D021122:Protein Subunits / Q000378:metabolism; D051381:Rats; D017465:Receptors, Opioid, delta / Q000819:agonists / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D014162:Transfection; D020764:cdc42 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*; D020744:rac GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018631:ras Proteins / Q000235:genetics / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D009294:Narcotics; D021122:Protein Subunits; D017465:Receptors, Opioid, delta; D011993:Recombinant Fusion Proteins; D020881:Enkephalin, D-Penicillamine (2,5)-; D019061:src-Family Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D019204:GTP-Binding Proteins; D020764:cdc42 GTP-Binding Protein; D020744:rac GTP-Binding Proteins; D018631:ras Proteins