Document Detail

beta 2-adrenergic receptor activates extracellular signal-regulated kinases (ERKs) via the small G protein rap1 and the serine/threonine kinase B-Raf.
MedLine Citation:
PMID:  10840035     Owner:  NLM     Status:  MEDLINE    
G protein-coupled receptors can induce cellular proliferation by stimulating the mitogen-activated protein (MAP) kinase cascade. Heterotrimeric G proteins are composed of both alpha and betagamma subunits that can signal independently to diverse intracellular signaling pathways including those that activate MAP kinases. In this study, we examined the ability of isoproterenol, an agonist of the beta(2)-adrenergic receptor (beta(2)AR), to stimulate extracellular signal-regulated kinases (ERKs). Using HEK293 cells, which express endogenous beta(2)AR, we show that isoproterenol stimulates ERKs via beta(2)AR. This action of isoproterenol requires cAMP-dependent protein kinase and is insensitive to pertussis toxin, suggesting that Galpha(s) activation of cAMP-dependent protein kinase is required. Interestingly, beta(2)AR activates both the small G proteins Rap1 and Ras, but only Rap1 is capable of coupling to Raf isoforms. beta(2)AR inhibits the Ras-dependent activation of both Raf isoforms Raf-1 and B-Raf, whereas Rap1 activation by isoproterenol recruits and activates B-Raf. beta(2)AR activation of ERKs is not blocked by expression of RasN17, an interfering mutant of Ras, but is blocked by expression of either RapN17 or Rap1GAP1, both of which interfere with Rap1 signaling. We propose that isoproterenol can activate ERKs via Rap1 and B-Raf in these cells.
J M Schmitt; P J Stork
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  275     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2000 Aug 
Date Detail:
Created Date:  2000-09-21     Completed Date:  2000-09-21     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  25342-50     Citation Subset:  IM    
Vollum Institute and the Department of Cell and Developmental Biology, Oregon Health Sciences University, Portland 97201, USA.
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MeSH Terms
Adrenergic beta-Agonists / pharmacology
Blotting, Western
Cell Line
Chromatography, Affinity
Cyclic AMP-Dependent Protein Kinases / metabolism
Dose-Response Relationship, Drug
Enzyme Activation / drug effects
Escherichia coli / metabolism
Glutathione Transferase / metabolism
Isoproterenol / pharmacology
Mitogen-Activated Protein Kinases / metabolism*
Nickel / metabolism
Pertussis Toxin
Plasmids / metabolism
Protein Isoforms
Proto-Oncogene Proteins c-raf / metabolism*
Receptors, Adrenergic, beta-2 / metabolism*
Recombinant Fusion Proteins / metabolism
Time Factors
Virulence Factors, Bordetella / pharmacology
rap1 GTP-Binding Proteins / metabolism*
ras Proteins / metabolism
Reg. No./Substance:
0/Adrenergic beta-Agonists; 0/Protein Isoforms; 0/Receptors, Adrenergic, beta-2; 0/Recombinant Fusion Proteins; 0/Virulence Factors, Bordetella; 7440-02-0/Nickel; 7683-59-2/Isoproterenol; EC Toxin; EC Transferase; EC Proteins c-raf; EC AMP-Dependent Protein Kinases; EC Protein Kinases; EC GTP-Binding Proteins; EC Proteins

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