title: Regulation of ERK1/2 by the C. elegans muscarinic acetylcholine receptor GAR-3 in Chinese hamster ovary cells.
abstract: Three G-protein-linked acetylcholine receptors (GARs) exist in the nematode C. elegans. GAR-3 is pharmacologically most similar to mammalian muscarinic acetylcholine receptors (mAChRs). We observed that carbachol stimulated ERK1/2 activation in Chinese hamster ovary (CHO) cells stably expressing GAR-3b, the predominant alternatively spliced isoform of GAR-3. This effect was substantially reduced by the phospholipase C (PLC) inhibitor U73122 and the protein kinase C (PKC) inhibitor GF109203X, implying that PLC and PKC are involved in this process. On the other hand, GAR-3b-mediated ERK1/2 activation was inhibited by treatment with forskolin, an adenylate cyclase (AC) activator. This inhibitory effect was blocked by H89, an inhibitor of cAMP-dependent protein kinase A (PKA). These results suggest that GAR-3b-mediated ERK1/2 activation is negatively regulated by cAMP through PKA. Together our data show that GAR-3b mediates ERK1/2 activation in CHO cells and that GAR-3b can couple to both stimulatory and inhibitory pathways to modulate ERK1/2.
authors.affiliation: School of Life Sciences, Chungbuk National University, Cheongju 361-763, Korea.
authors.forename: Seungwoo
authors.initials: S
authors.lastname: Kim
authors.forename: Youngmi
authors.initials: Y
authors.lastname: Shin
authors.forename: Youngju
authors.initials: Y
authors.lastname: Shin
authors.forename: Yang-Seo
authors.initials: YS
authors.lastname: Park
authors.forename: Nam Jeong
authors.initials: NJ
authors.lastname: Cho
mesh_terms: D017398:Alternative Splicing; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D016466:CHO Cells; D017173:Caenorhabditis elegans / Q000201:enzymology / Q000235:genetics; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D002217:Carbachol / Q000494:pharmacology; D005576:Colforsin / Q000819:agonists / Q000494:pharmacology; D006224:Cricetinae; D003412:Cricetulus; D000242:Cyclic AMP / Q000819:agonists / Q000096:biosynthesis / Q000235:genetics; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D004789:Enzyme Activation / Q000187:drug effects / Q000235:genetics; D004963:Estrenes / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics* / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics* / Q000378:metabolism; D018721:Muscarinic Agonists / Q000494:pharmacology; D018727:Muscarinic Antagonists / Q000494:pharmacology; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011760:Pyrrolidinones / Q000494:pharmacology; D011976:Receptors, Muscarinic / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013449:Sulfonamides / Q000494:pharmacology; D014162:Transfection; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors
chemical_list: D029742:Caenorhabditis elegans Proteins; D004963:Estrenes; C477876:GAR-3 protein, C elegans; D007211:Indoles; D007546:Isoquinolines; D008301:Maleimides; D018721:Muscarinic Agonists; D018727:Muscarinic Antagonists; D020033:Protein Isoforms; D011760:Pyrrolidinones; D011976:Receptors, Muscarinic; D011994:Recombinant Proteins; D013449:Sulfonamides; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D005576:Colforsin; D001285:Atropine; D002217:Carbachol; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D010738:Type C Phospholipases; C070515:bisindolylmaleimide I; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide