GIPC interacts with the beta1-adrenergic receptor and regulates beta1-adrenergic receptor-mediated ERK activation.
Beta1-adrenergic receptors, expressed at high levels in the human heart, have a carboxyl-terminal ESKV motif that can directly interact with PDZ domain-containing proteins. Using the beta1-adrenergic receptor carboxyl terminus as bait, we identified the novel beta1-adrenergic receptor-binding partner GIPC in a yeast two-hybrid screen of a human heart cDNA library. Here we demonstrate that the PDZ domain-containing protein, GIPC, co-immunoprecipitates with the beta1-adrenergic receptor in COS-7 cells. Essential for this interaction is the Ser residue of the beta1-adrenergic receptor carboxyl-terminal ESKV motif. Our data also demonstrate that beta1-adrenergic receptor stimulation activates the mitogen-activated protein kinase, ERK1/2. beta1-adrenergic receptor-mediated ERK1/2 activation was inhibited by pertussis toxin, implicating Gi, and was substantially decreased by the expression of GIPC. Expression of GIPC had no observable effect on beta1-adrenergic receptor sequestration or receptor-mediated cAMP accumulation. This GIPC effect was specific for the beta1-adrenergic receptor and was dependent on an intact PDZ binding motif. These data suggest that GIPC can regulate beta1-adrenergic receptor-stimulated, Gi-mediated, ERK activation while having no effect on receptor internalization or Gs-mediated cAMP signaling.
Howard Hughes Medical Institute, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA.
Liaoyuan A
LA
Hu
Wei
W
Chen
Negin P
NP
Martin
Erin J
EJ
Whalen
Richard T
RT
Premont
Robert J
RJ
Lefkowitz
D048868:Adaptor Proteins, Signal Transducing; D020816:Amino Acid Motifs; D000818:Animals; D019556:COS Cells; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D015971:Gene Expression Regulation, Enzymologic; D015723:Gene Library; D006801:Humans; D015151:Immunoblotting; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism*; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D018342:Receptors, Adrenergic, beta-1 / Q000378:metabolism*; D012694:Serine / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection; D020798:Two-Hybrid System Techniques
D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D018076:DNA, Complementary; C492009:GIPC1 protein, human; D009479:Neuropeptides; D018342:Receptors, Adrenergic, beta-1; D012694:Serine; D000242:Cyclic AMP; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases