Journal Article

Cryo-EM structure of an activated GPCR–G protein complex in lipid nanodiscs

Hagn, Franz, Wu, Hao, Wagner, Gerhard, Brown, Alan, Wang, Zi-Fu, Gorgulla, Christoph, Sun, Zhen-yu J., Klenk, Christoph, Morstein, Lena, Merklinger, Lisa, Gui, Miao, Plückthun, Andreas, Zhang, Meng, Yu, James J., Nasr, Mahmoud L.

2021

Overview

G-protein-coupled receptors (GPCRs) are the largest superfamily of transmembrane proteins and the targets of over 30% of currently marketed pharmaceuticals. Although several structures have been solved for GPCR–G protein complexes, few are in a lipid membrane environment. Here, we report cryo-EM structures of complexes of neurotensin, neurotensin receptor 1 and Gα i1 β 1 γ 1 in two conformational states, resolved to resolutions of 4.1 and 4.2 Å. The structures, determined in a lipid bilayer without any stabilizing antibodies or nanobodies, reveal an extended network of protein–protein interactions at the GPCR–G protein interface as compared to structures obtained in detergent micelles. The findings show that the lipid membrane modulates the structure and dynamics of complex formation and provide a molecular explanation for the stronger interaction between GPCRs and G proteins in lipid bilayers. We propose an allosteric mechanism for GDP release, providing new insights into the activation of G proteins for downstream signaling. Structures of GPCR neurotensin receptor 1 (NTSR1) in complex with neurotensin and Gα i1 β 1 γ 1 in a lipid bilayer environment and without stabilizing antibodies reveal extensive interactions at the GPCR–G protein interface.

• Publisher: Nature Publishing Group US,Nature Publishing Group
• Subject: 101/28 / 631/45/535/1258/1259 / 631/535/1258/1259 / Allosteric properties / Allosteric Regulation / Antibodies / Biochemistry / Biological Microscopy / Biomedical and Life Sciences / Complex formation / Cryoelectron Microscopy / G protein-coupled receptors / GTP-Binding Protein alpha Subunits, Gi-Go - chemistry / GTP-Binding Protein alpha Subunits, Gi-Go - metabolism / GTP-Binding Protein alpha Subunits, Gi-Go - ultrastructure / GTP-Binding Protein beta Subunits - chemistry / GTP-Binding Protein beta Subunits - metabolism / GTP-Binding Protein beta Subunits - ultrastructure / GTP-Binding Protein gamma Subunits - chemistry / GTP-Binding Protein gamma Subunits - metabolism / GTP-Binding Protein gamma Subunits - ultrastructure / Guanosine Diphosphate - metabolism / Heterotrimeric GTP-Binding Proteins - chemistry / Heterotrimeric GTP-Binding Proteins - metabolism / Heterotrimeric GTP-Binding Proteins - ultrastructure / Humans / Life Sciences / Lipid bilayers / Lipid Bilayers - chemistry / Lipid Bilayers - metabolism / Lipids / Membrane Biology / Membrane proteins / Membranes / Micelles / Models, Molecular / Nanobodies / Nanostructures - chemistry / Neurotensin / Neurotensin - chemistry / Neurotensin - metabolism / Protein Conformation / Protein interaction / Protein Structure / Proteins / Receptors / Receptors, Neurotensin - chemistry / Receptors, Neurotensin - metabolism / Receptors, Neurotensin - ultrastructure / Signal Transduction