A novel function of Goalpha: mediation of extracellular signal-regulated kinase activation by opioid receptors in neural cells.
Go is the most abundant G protein expressed in brain but its function is less known. Here we show a novel function of Goalpha as a mediator of opioid receptor-induced extracellular signal-regulated kinase activation in neural cells. The current study found that, in neuroblastoma x glioma NG108-15 hybrid cells, activation of extracellular signal-regulated kinase through delta opioid receptors was mediated by pertussis toxin-sensitive G protein and independent of Gbetagamma subunits, PI3 kinase and receptor internalization. Overexpression of a dominant negative form of Goalpha1, but not Gialpha2, completely blocked delta opioid receptor-induced extracellular signal-regulated kinase activity. Decreasing Goalpha expression by RNA interference greatly reduced delta opioid receptor-induced extracellular signal-regulated kinase activity and extracellular signal-regulated kinase-dependent gene expression, while knocking down Gialpha2 did not. By taking advantage of differences between human and mouse Goalpha gene sequences, we simultaneously knocked down endogenous Goalpha expression and expressed exogenous human Goalpha subunits. We found that both human Goalpha1 and Goalpha2 could mediate delta opioid receptor-induced extracellular signal-regulated kinase activation. This study suggests that one of the functions of Goalpha in the brain is to mediate extracellular signal-regulated kinase activation by G protein-coupled receptors.
Zhang
Wen-Bo
WB
Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China.
Zhang
Zhe
Z
Ni
Yan-Xiang
YX
Wu
Ya-Lan
YL
Pei
Gang
G
D000818:Animals; D002460:Cell Line; D004268:DNA-Binding Proteins; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D005799:Genes, Dominant; D017930:Genes, Reporter; D005910:Glioma / Q000378:metabolism; D020962:Heterotrimeric GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D006801:Humans; D006822:Hybrid Cells / Q000378:metabolism; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009447:Neuroblastoma / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D037342:Pertussis Toxin / Q000494:pharmacology; D021122:Protein Subunits / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D017465:Receptors, Opioid, delta / Q000378:metabolism*; D014157:Transcription Factors; D014162:Transfection; D050807:ets-Domain Protein Elk-1
D004268:DNA-Binding Proteins; C494114:Elk1 protein, rat; D021122:Protein Subunits; D011518:Proto-Oncogene Proteins; D034741:RNA, Small Interfering; D017465:Receptors, Opioid, delta; D014157:Transcription Factors; D050807:ets-Domain Protein Elk-1; D037342:Pertussis Toxin; D020928:Mitogen-Activated Protein Kinases; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D020962:Heterotrimeric GTP-Binding Proteins