Tyrosine 308 Is Necessary for Ligand-directed Gs Protein-biased Signaling of β2-Adrenoceptor

• DOI: 10.1074/jbc.m114.558882
• Publication Date: 2014-05-16T05:47:01Z
• Authors: Anthony Yiu-Ho Woo; Krzysztof Jozwiak; Lawrence Toll; Mary J. Tanga; Joseph A. Kozocas; Lucita Jimenez; Ying Huang; Ying Song; Anita Plazinska; Karolina Pajak; Rajib K. Paul; Michel Bernier; Irving W. Wainer; Rui-Ping Xiao
• Keywords: Male; Mice, Knockout; 0303 health sciences; Protein Stability; Mutation, Missense; Rats; Rats, Sprague-Dawley; Mice; 03 medical and health sciences; HEK293 Cells; Amino Acid Substitution; Animals; Humans; Tyrosine; Myocytes, Cardiac; Receptors, Adrenergic, beta-2; Phosphorylation; Extracellular Signal-Regulated MAP Kinases; Adrenergic beta-2 Receptor Agonists; Signal Transduction

Interaction of a given G protein-coupled receptor to multiple different proteins is widespread phenomenon. For instance, β2-adrenoceptor (β2-AR) couples dually Gs and Gi proteins. Previous studies have shown that cAMP-dependent protein kinase (PKA)-mediated phosphorylation β2-AR causes switch in coupling from Gi. More recent demonstrated by kinases, particularly GRK2, markedly enhances the coupling. We previously although most agonists cause both activation, (R,R′)-fenoterol preferentially activates β2-AR-Gs signaling. However, structural basis for this functional selectivity remains elusive. Here, using docking simulation site-directed mutagenesis, we defined Tyr-308 as key amino acid residue on essential Gs-biased Following stimulation with β2-AR-Gs-biased agonist (R,R′)-4′-aminofenoterol, disruptor pertussis toxin produced no effects receptor-mediated ERK HEK293 cells nor contractile response cardiomyocytes expressing wild-type β2-AR. Interestingly, Y308F substitution enabled (R,R′)-4′-aminofenoterol activate produce these responses toxin-sensitive manner without altering PKA or kinases. These results indicate that, addition status, intrinsic feature plays crucial role conclude specific interactions between ligand stabilize conformations favoring receptor-Gs subsequently result agonism.