Ligand recognition mechanism of the human relaxin family peptide receptor 4 (RXFP4)

  • Nat Commun. 2023 Jan 30;14(1):492. doi: 10.1038/s41467-023-36182-z.
Yan Chen  #  1 ,  Qingtong Zhou  #  1 ,  Jiang Wang  #  2  3  4 ,  Youwei Xu  5 ,  Yun Wang  6 ,  Jiahui Yan  5  7  8 ,  Yibing Wang  2 ,  Qi Zhu  6 ,  Fenghui Zhao  5  7 ,  Chenghao Li  2  4 ,  Chuan-Wei Chen  9 ,  Xiaoqing Cai  5  7 ,  Ross A D Bathgate  10  11 ,  Chun Shen  6 ,  H Eric Xu  5  8  12 ,  Dehua Yang  13  14  15  16 ,  Hong Liu  17  18  19  20 ,  Ming-Wei Wang  21  22  23  24  25  26
Affiliations
  • 1. Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China.
  • 2. State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
  • 3. Lingang Laboratory, Shanghai, 200031, China.
  • 4. School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, UCAS, Hangzhou, 310024, China.
  • 5. The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
  • 6. Genova Biotech (Changzhou) Co., Ltd, Changzhou, 213125, China.
  • 7. The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
  • 8. University of Chinese Academy of Sciences, Beijing, 100049, China.
  • 9. Research Center for Deepsea Bioresources, Sanya, Hainan, 572025, China.
  • 10. The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, 3052, Australia.
  • 11. Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, 3052, Australia.
  • 12. School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China.
  • 13. The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China. [email protected].
  • 14. The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China. [email protected].
  • 15. University of Chinese Academy of Sciences, Beijing, 100049, China. [email protected].
  • 16. Research Center for Deepsea Bioresources, Sanya, Hainan, 572025, China. [email protected].
  • 17. State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China. [email protected].
  • 18. School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, UCAS, Hangzhou, 310024, China. [email protected].
  • 19. University of Chinese Academy of Sciences, Beijing, 100049, China. [email protected].
  • 20. School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China. [email protected].
  • 21. Department of Pharmacology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China. [email protected].
  • 22. The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China. [email protected].
  • 23. The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China. [email protected].
  • 24. University of Chinese Academy of Sciences, Beijing, 100049, China. [email protected].
  • 25. Research Center for Deepsea Bioresources, Sanya, Hainan, 572025, China. [email protected].
  • 26. Department of Chemistry, School of Science, The University of Tokyo, Tokyo, 113-0033, Japan. [email protected].
  • # Contributed equally.
PMID: 36717591 DOI: 10.1038/s41467-023-36182-z
Abstract

Members of the Insulin superfamily regulate pleiotropic biological processes through two types of target-specific but structurally conserved Peptides, Insulin/insulin-like growth factors and relaxin/insulin-like Peptides. The latter bind to the human relaxin family peptide receptors (RXFPs). Here, we report three cryo-electron microscopy structures of RXFP4-Gi protein complexes in the presence of the endogenous ligand insulin-like peptide 5 (INSL5) or one of the two small molecule agonists, compound 4 and DC591053. The B chain of INSL5 adopts a single α-helix that penetrates into the orthosteric pocket, while the A chain sits above the orthosteric pocket, revealing a peptide-binding mode previously unknown. Together with mutagenesis and functional analyses, the key determinants responsible for the peptidomimetic agonism and subtype selectivity were identified. Our findings not only provide insights into ligand recognition and subtype selectivity among class A G protein-coupled receptors, but also expand the knowledge of signaling mechanisms in the Insulin superfamily.