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Coupling Of Smoothened To Inhibitory G Proteins Reduces Voltage-Gated K, Lan Cheng, Moza Al-Owais, Manuel Covarrubias, Walter J. Koch, David R. Manning, Chris Peers, Natalia A Riobo-Del Galdo

Department of Biochemistry and Molecular Biology Faculty Papers

SMO (Smoothened), the central transducer of Hedgehog signaling, is coupled to heterotrimeric G_i proteins in many cell types, including cardiomyocytes. In this study, we report that activation of SMO with SHH (Sonic Hedgehog) or a small agonist, purmorphamine, rapidly causes a prolongation of the action potential duration that is sensitive to a SMO inhibitor. In contrast, neither of the SMO agonists prolonged the action potential in cardiomyocytes from transgenic G_iCT/TTA mice, in which G_i signaling is impaired, suggesting that the effect of SMO is mediated by G_i proteins. Investigation of the mechanism underlying the change …