Kappa-opioid receptor signals through Src and focal adhesion kinase to stimulate c-Jun N-terminal kinases in transfected COS-7 cells and human monocytic THP-1 cells.
Opioid peptides exert diverse physiological functions through their cognate receptors. One subtype of the opioid receptors, kappa-opioid receptor, is endogenously expressed in human monocytic THP-1 cells. Stimulation of the THP-1 cells with a kappa-opioid receptor-selective agonist exerted a Gi-dependent activation of c-Jun N-terminal kinase (JNK). To further investigate the signaling mechanism by which the kappa-opioid receptor regulates JNK activity, heterologous expression assays in COS-7 cells were utilized. Overexpression of Galphat in COS-7 cells clearly suppressed kappa-opioid receptor-stimulated JNK activity, indicating that the pathway is primarily regulated by Gbetagamma. In both THP-1 and transfected COS-7 cells, pretreatment of the selective Src family kinase inhibitor pyrazolopyrimidine PP1 abolished the JNK activation, whereas the epidermal growth factor receptor inhibitor AG1478 [N-(3-chlorophenyl)-6,7-dimethoxy-4-quinazolinanine] failed to do that. Furthermore, the JNK activation in response to kappa-opioid receptor was suppressed by an autophosphorylation-resistant mutant of focal adhesion kinase (FAK). Consistently, activated kappa-opioid receptor induced Src stimulation and FAK autophosphorylation and promoted the formation of Src-FAK complex. The participation of small GTPases as well as a guanine nucleotide exchange factor was also implicated because dominant-negative mutants of Rac, Cdc42, and Son-of-sevenless (Sos) attenuated the agonist-induced activation of JNK. These studies demonstrate that the activation of JNK by kappa-opioid receptors is routed via Gbetagamma, Src, FAK, Sos, Rac, and Cdc42.
Department of Biochemistry, the Molecular Neuroscience Center, and the Biotechnology Research Institute, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
Angel Y F
AY
Kam
Anthony S L
AS
Chan
Yung H
YH
Wong
D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D004268:DNA-Binding Proteins; D004789:Enzyme Activation; D066246:ErbB Receptors / Q000378:metabolism; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D020558:GTP Phosphohydrolases / Q000378:metabolism; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases; D020935:MAP Kinase Signaling System; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D009000:Monocytes / Q000201:enzymology / Q000378:metabolism*; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D017473:Receptors, Opioid, kappa / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism; D014162:Transfection; D019061:src-Family Kinases / Q000378:metabolism*
D004268:DNA-Binding Proteins; D017473:Receptors, Opioid, kappa; C480633:SLC2A4RG protein, human; D014157:Transcription Factors; D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; D019061:src-Family Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D020558:GTP Phosphohydrolases; D019206:GTP-Binding Protein alpha Subunits, Gi-Go