Structure insights into selective coupling of G protein subtypes by a class B G protein-coupled receptor.

Zhao, Li-Hua; Lin, Jingyu; Ji, Su-Yu; Zhou, X Edward; Mao, Chunyou; Shen, Dan-Dan; He, Xinheng; Xiao, Peng et al. · Nat Commun · 2022

basic_science · Level V

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Abstract

The ability to couple with multiple G protein subtypes, such as G<sub>s</sub>, G<sub>i/o</sub>, or G<sub>q/11</sub>, by a given G protein-coupled receptor (GPCR) is critical for many physiological processes. Over the past few years, the cryo-EM structures for all 15 members of the medically important class B GPCRs, all in complex with G<sub>s</sub> protein, have been determined. However, no structure of class B GPCRs with G<sub>q/11</sub> has been solved to date, limiting our understanding of the precise mechanisms of G protein coupling selectivity. Here we report the structures of corticotropin releasing factor receptor 2 (CRF2R) bound to Urocortin 1 (UCN1), coupled with different classes of heterotrimeric G proteins, G<sub>11</sub> and G<sub>o</sub>. We compare these structures with the structure of CRF2R in complex with G<sub>s</sub> to uncover the structural differences that determine the selective coupling of G protein subtypes by CRF2R. These results provide important insights into the structural basis for the ability of CRF2R to couple with multiple G protein subtypes.

Medical subject headings