Molecular mechanism of the endothelin receptor type B interactions with Gs, Gi, and Gq

Donghee Ham; Wataru Shihoya; Osamu Nureki; Asuka Inoue; Ka Young Chung

doi:10.1016/j.str.2024.06.020

Molecular mechanism of the endothelin receptor type B interactions with Gs, Gi, and Gq

Structure. 2024 Oct 3;32(10):1632-1639.e4. doi: 10.1016/j.str.2024.06.020. Epub 2024 Jul 22.

Authors

Donghee Ham¹, Wataru Shihoya², Osamu Nureki², Asuka Inoue³, Ka Young Chung⁴

Affiliations

¹ School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea.
² Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bumkyo-ku, Tokyo 113-0033, Japan.
³ Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578, Japan; Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida-Shimo-Adachi-cho, Sakyo-ku, Kyoto 606-8501, Japan. Electronic address: iaska@tohoku.ac.jp.
⁴ School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea. Electronic address: kychung2@skku.edu.

PMID: 39043181
DOI: 10.1016/j.str.2024.06.020

Abstract

The endothelin receptor type B (ET_B) exhibits promiscuous coupling with various heterotrimeric G protein subtypes including Gs, Gi/o, Gq/11, and G12/13. Recent fluorescence and structural studies have raised questions regarding the coupling efficiencies and determinants of these G protein subtypes. Herein, by utilizing an integrative approach, combining hydrogen/deuterium exchange mass spectrometry and NanoLuc Binary Technology-based cellular systems, we investigated conformational changes of Gs, Gi, and Gq triggered by ET_B activation. ET_B coupled to Gi and Gq but not with Gs. We underscored the critical roles of specific regions, including the C terminus of Gα and intracellular loop 2 (ICL2) of ET_B in ET_B-Gi1 or ET_B-Gq coupling. Although The C terminus of Gα is essential for ET_B-Gi1 and ET_B-Gq coupling, ET_B ICL2 influences Gq-coupling but not Gi1-coupling. Our results suggest a differential coupling efficiency of ET_B with Gs, Gi1, and Gq, accompanied by distinct conformational changes in G proteins upon ET_B-induced activation.

Keywords: ET(B); G protein; HDX-MS; conformation; signal selectivity.

MeSH terms

Binding Sites
GTP-Binding Protein alpha Subunits, Gi-Go* / chemistry
GTP-Binding Protein alpha Subunits, Gi-Go* / genetics
GTP-Binding Protein alpha Subunits, Gi-Go* / metabolism
GTP-Binding Protein alpha Subunits, Gq-G11* / chemistry
GTP-Binding Protein alpha Subunits, Gq-G11* / metabolism
GTP-Binding Protein alpha Subunits, Gs / chemistry
GTP-Binding Protein alpha Subunits, Gs / metabolism
HEK293 Cells
Humans
Models, Molecular
Protein Binding*
Protein Conformation
Receptor, Endothelin B* / chemistry
Receptor, Endothelin B* / metabolism

Substances

EDNRB protein, human
GTP-Binding Protein alpha Subunits, Gi-Go
GTP-Binding Protein alpha Subunits, Gq-G11
GTP-Binding Protein alpha Subunits, Gs
Receptor, Endothelin B
GNAS protein, human
GNAQ protein, human
GNAI1 protein, human