Insights into divalent cation regulation and G13-coupling of orphan receptor GPR35

Jia Duan; Qiufeng Liu; Qingning Yuan; Yujie Ji; Shengnan Zhu; Yangxia Tan; Xinheng He; Youwei Xu; Jingjing Shi; Xi Cheng; Hualiang Jiang; H Eric Xu; Yi Jiang

doi:10.1038/s41421-022-00499-8

Insights into divalent cation regulation and G₁₃-coupling of orphan receptor GPR35

Cell Discov. 2022 Dec 21;8(1):135. doi: 10.1038/s41421-022-00499-8.

Authors

Jia Duan^#^{1

2}, Qiufeng Liu^#¹, Qingning Yuan^#¹, Yujie Ji^{1

2}, Shengnan Zhu³, Yangxia Tan¹, Xinheng He^{1

2}, Youwei Xu¹, Jingjing Shi¹, Xi Cheng^{1

2

4}, Hualiang Jiang^{1

2

4

5

6}, H Eric Xu^{7

8

9

10}, Yi Jiang^{11

12}

Affiliations

¹ CAS Key Laboratory of Receptor Research, Center for Structure and Function of Drug Targets, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
² University of Chinese Academy of Sciences, Beijing, China.
³ School of Pharmacy, Macau University of Science and Technology, Macau, China.
⁴ School of Pharmaceutical Science and Technology, Hangzhou Institute of Advanced Study, Hangzhou, Zhejiang, China.
⁵ School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
⁶ State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
⁷ CAS Key Laboratory of Receptor Research, Center for Structure and Function of Drug Targets, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China. eric.xu@simm.ac.cn.
⁸ University of Chinese Academy of Sciences, Beijing, China. eric.xu@simm.ac.cn.
⁹ School of Life Science and Technology, ShanghaiTech University, Shanghai, China. eric.xu@simm.ac.cn.
¹⁰ State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China. eric.xu@simm.ac.cn.
¹¹ School of Life Science and Technology, ShanghaiTech University, Shanghai, China. yjiang@lglab.ac.cn.
¹² Lingang Laboratory, Shanghai, China. yjiang@lglab.ac.cn.

^# Contributed equally.

Abstract

Endogenous ions play important roles in the function and pharmacology of G protein-coupled receptors (GPCRs) with limited atomic evidence. In addition, compared with G protein subtypes G_s, G_i/o, and G_q/11, insufficient structural evidence is accessible to understand the coupling mechanism of G_12/13 protein by GPCRs. Orphan receptor GPR35, which is predominantly expressed in the gastrointestinal tract and is closely related to inflammatory bowel diseases (IBDs), stands out as a prototypical receptor for investigating ionic modulation and G₁₃ coupling. Here we report a cryo-electron microscopy structure of G₁₃-coupled GPR35 bound to an anti-allergic drug, lodoxamide. This structure reveals a novel divalent cation coordination site and a unique ionic regulatory mode of GPR35 and also presents a highly positively charged binding pocket and the complementary electrostatic ligand recognition mode, which explain the promiscuity of acidic ligand binding by GPR35. Structural comparison of the GPR35-G₁₃ complex with other G protein subtypes-coupled GPCRs reveals a notable movement of the C-terminus of α5 helix of the Gα₁₃ subunit towards the receptor core and the least outward displacement of the cytoplasmic end of GPR35 TM6. A featured 'methionine pocket' contributes to the G₁₃ coupling by GPR35. Together, our findings provide a structural basis for divalent cation modulation, ligand recognition, and subsequent G₁₃ protein coupling of GPR35 and offer a new opportunity for designing GPR35-targeted drugs for the treatment of IBDs.