| Author |
Pajak, Karolina Woo, Anthony Yiu-ho Kozocas, Joseph A. Bernier, Michel Toll, Lawrence Plazinska, Anita Paul, Rajib K. Song, Ying Jimenez, Lucita Jozwiak, Krzysztof Wainer, Irving W. Xiao, Rui-ping Huang, Ying Tanga, Mary J. |
| Description |
Author Affiliation: Woo AY ( From the Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China, the Institute of Molecular Medicine, Centers for Life Sciences, Peking University, Beijing 100871, China, the Laboratory of Cardiovascular S); Jozwiak K ( the Department of Chemistry, Medical University of Lublin, Lublin, Poland.); Toll L ( the Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida 34987, and.); Tanga MJ ( SRI International, Menlo Park, California 94025.); Kozocas JA ( SRI International, Menlo Park, California 94025.); Jimenez L ( SRI International, Menlo Park, California 94025.); Huang Y ( From the Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China, the Institute of Molecular Medicine, Centers for Life Sciences, Peking University, Beijing 100871, China.); Song Y ( From the Key Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055, China, the Institute of Molecular Medicine, Centers for Life Sciences, Peking University, Beijing 100871, China.); Plazinska A ( the Department of Chemistry, Medical University of Lublin, Lublin, Poland.); Pajak K ( the Department of Chemistry, Medical University of Lublin, Lublin, Poland.); Paul RK ( Laboratory of Clinical Investigation, NIA, National Institutes of Health, Baltimore, Maryland 21224.); Bernier M ( Laboratory of Clinical Investigation, NIA, National Institutes of Health, Baltimore, Maryland 21224.); Wainer IW ( Laboratory of Clinical Investigation, NIA, National Institutes of Health, Baltimore, Maryland 21224.); Xiao RP ( the Institute of Molecular Medicine, Centers for Life Sciences, Peking University, Beijing 100871, China, xiaor@pku.edu.cn.) |
| Abstract |
Interaction of a given G protein-coupled receptor to multiple different G proteins is a widespread phenomenon. For instance, ß2-adrenoceptor (ß2-AR) couples dually to Gs and Gi proteins. Previous studies have shown that cAMP-dependent protein kinase (PKA)-mediated phosphorylation of ß2-AR causes a switch in receptor coupling from Gs to Gi. More recent studies have demonstrated that phosphorylation of ß2-AR by G protein-coupled receptor kinases, particularly GRK2, markedly enhances the Gi coupling. We have previously shown that although most ß2-AR agonists cause both Gs and Gi activation, (R,R')-fenoterol preferentially activates ß2-AR-Gs signaling. However, the structural basis for this functional selectivity remains elusive. Here, using docking simulation and site-directed mutagenesis, we defined Tyr-308 as the key amino acid residue on ß2-AR essential for Gs-biased signaling. Following stimulation with a ß2-AR-Gs-biased agonist (R,R')-4'-aminofenoterol, the Gi disruptor pertussis toxin produced no effects on the receptor-mediated ERK phosphorylation in HEK293 cells nor on the contractile response in cardiomyocytes expressing the wild-type ß2-AR. Interestingly, Y308F substitution on ß2-AR enabled (R,R')-4'-aminofenoterol to activate Gi and to produce these responses in a pertussis toxin-sensitive manner without altering ß2-AR phosphorylation by PKA or G protein-coupled receptor kinases. These results indicate that, in addition to the phosphorylation status, the intrinsic structural feature of ß2-AR plays a crucial role in the receptor coupling selectivity to G proteins. We conclude that specific interactions between the ligand and the Tyr-308 residue of ß2-AR stabilize receptor conformations favoring the receptor-Gs protein coupling and subsequently result in Gs-biased agonism. |
| Subject Keyword |
Myocytes, Cardiac Metabolism Receptors, Adrenergic, Beta-2 Signal Transduction Physiology Adrenergic Beta-2 Receptor Agonists Pharmacology Amino Acid Substitution Animals Extracellular Signal-Regulated MAP Kinases Genetics HEK293 Cells Mice Mice, Knockout Mutation, Missense Cytology Phosphorylation Drug Effects Protein Stability Rats, Sprague-Dawley Tyrosine Research Support, N.I.H., Extramural Research Support, N.I.H., Intramural Research Support, Non-U.S. Gov't Biochemistry Molecular Biology |
