ジャーナル: Nat Commun / 年: 2023 タイトル: Molecular architecture of the Gα-bound TRPC5 ion channel. 著者: Jongdae Won / Jinsung Kim / Hyeongseop Jeong / Jinhyeong Kim / Shasha Feng / Byeongseok Jeong / Misun Kwak / Juyeon Ko / Wonpil Im / Insuk So / Hyung Ho Lee / 要旨: G-protein coupled receptors (GPCRs) and ion channels serve as key molecular switches through which extracellular stimuli are transformed into intracellular effects, and it has long been postulated ...G-protein coupled receptors (GPCRs) and ion channels serve as key molecular switches through which extracellular stimuli are transformed into intracellular effects, and it has long been postulated that ion channels are direct effector molecules of the alpha subunit of G-proteins (Gα). However, no complete structural evidence supporting the direct interaction between Gα and ion channels is available. Here, we present the cryo-electron microscopy structures of the human transient receptor potential canonical 5 (TRPC5)-Gα complexes with a 4:4 stoichiometry in lipid nanodiscs. Remarkably, Gα binds to the ankyrin repeat edge of TRPC5 ~ 50 Å away from the cell membrane. Electrophysiological analysis shows that Gα increases the sensitivity of TRPC5 to phosphatidylinositol 4,5-bisphosphate (PIP), thereby rendering TRPC5 more easily opened in the cell membrane, where the concentration of PIP is physiologically regulated. Our results demonstrate that ion channels are one of the direct effector molecules of Gα proteins triggered by GPCR activation-providing a structural framework for unraveling the crosstalk between two major classes of transmembrane proteins: GPCRs and ion channels.
解像度のタイプ: BY AUTHOR / 解像度: 3.91 Å / 解像度の算出法: OTHER 詳細: We combined two different maps from the same dataset (D_1300031718_em-additional-volume_P1.map.V4 and D_1300031718_em-additional-volume_P2.map.V4) to generate a composite map (D_1300031718_em- ...詳細: We combined two different maps from the same dataset (D_1300031718_em-additional-volume_P1.map.V4 and D_1300031718_em-additional-volume_P2.map.V4) to generate a composite map (D_1300031718_em-volume_P1.map.V6). The density of the G protein area could not be visualized clearly in the consensus map of this EM dataset. Therefore, we performed focused classification and local refinement to improve the density of the G protein area using symmetry expanded particles with C4 symmetry imposition, which required more number of particles. Finally, the number of particles used to reconstruct additional volume data 1 (D_1300031718_em-additional-volume_P1.map.V4) is 5,344 and the number of particles used to reconstruct additional volume data 2 (D_1300031718_em-additional-volume_P2.map.V4) is 205,343. Furthermore, the resolution stated above is based on map resolution estimates calculated by a validation tool in Phenix, FSC (model) = 0.143. 使用した粒子像数: 5344