Analysis of ?2AR-Gs and ?2AR-Gi complex formation by NMR spectroscopy.
Related Articles Analysis of ?2AR-Gs and ?2AR-Gi complex formation by NMR spectroscopy.
Proc Natl Acad Sci U S A. 2020 Aug 31;:
Authors: Ma X, Hu Y, Batebi H, Heng J, Xu J, Liu X, Niu X, Li H, Hildebrand PW, Jin C, Kobilka BK
Abstract
The ?2-adrenergic receptor (?2AR) is a prototypical G protein-coupled receptor (GPCR) that preferentially couples to the stimulatory G protein Gs and stimulates cAMP formation. Functional studies have shown that the ?2AR also couples to inhibitory G protein Gi, activation of which inhibits cAMP formation [R. P. Xiao, Sci. STKE 2001, re15 (2001)]. A crystal structure of the ?2AR-Gs complex revealed the interaction interface of ?2AR-Gs and structural changes upon complex formation [S. G. Rasmussen et al., Nature 477, 549-555 (2011)], yet, the dynamic process of the ?2AR signaling through Gs and its preferential coupling to Gs over Gi is still not fully understood. Here, we utilize solution nuclear magnetic resonance (NMR) spectroscopy and supporting molecular dynamics (MD) simulations to monitor the conformational changes in the G protein coupling interface of the ?2AR in response to the full agonist BI-167107 and Gs and Gi1 These results show that BI-167107 stabilizes conformational changes in four transmembrane segments (TM4, TM5, TM6, and TM7) prior to coupling to a G protein, and that the agonist-bound receptor conformation is different from the G protein coupled state. While most of the conformational changes observed in the ?2AR are qualitatively the same for Gs and Gi1, we detected distinct differences between the ?2AR-Gs and the ?2AR-Gi1 complex in intracellular loop 2 (ICL2). Interactions with ICL2 are essential for activation of Gs These differences between the ?2AR-Gs and ?2AR-Gi1 complexes in ICL2 may be key determinants for G protein coupling selectivity.
PMID: 32868434 [PubMed - as supplied by publisher]
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