1. Structural Biology and Molecular Biophysics
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Structural insights into the activation of human calcium-sensing receptor

  1. Xiaochen Chen
  2. Lu Wang
  3. Qianqian Cui
  4. Zhanyu Ding
  5. Li Han
  6. Yongjun Kou
  7. Wenqing Zhang
  8. Haonan Wang
  9. Xiaomin Jia
  10. Mei Dai
  11. Zhenzhong Shi
  12. Yuying Li
  13. Xiyang Li
  14. Yong Geng  Is a corresponding author
  1. Shanghai Institute of Materia Medica, Chinese Academy of Sciences, China
Research Article
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Cite this article as: eLife 2021;10:e68578 doi: 10.7554/eLife.68578

Abstract

Human calcium-sensing receptor (CaSR) is a G-protein-coupled receptor that maintains Ca2+ homeostasis in serum. Here, we present the cryo-electron microscopy structures of the CaSR in the inactive and agonist+PAM bound states. Complemented with previously reported structures of CaSR, we show that in addition to the full inactive and active states, there are multiple intermediate states during the activation of CaSR. We used a negative allosteric nanobody to stabilize the CaSR in the fully inactive state and found a new binding site for Ca2+ ion that acts as a composite agonist with L-amino acid to stabilize the closure of active Venus flytraps. Our data show that agonist binding leads to compaction of the dimer, proximity of the cysteine-rich domains, large-scale transitions of 7-transmembrane domains, and inter- and intrasubunit conformational changes of 7-transmembrane domains to accommodate downstream transducers. Our results reveal the structural basis for activation mechanisms of CaSR and clarify the mode of action of Ca2+ ions and L-amino acid leading to the activation of the receptor.

Data availability

All data is available in the main text or the supplementary materials. Cryo-EM maps of active CaSR in complex with TNCA and inactive CaSR in complex with NB-2D11 have been deposited in the Electron Microscopy Data Bank under accession codes: EMD-30997 (NB-2D11 bound CaSR), EMD-30996 (TNCA bound CaSR). Atomic coordinates for the CaSR in complex with TNCA or NB-2D11 have been deposited in the Protein Data Bank under accession codes: 7E6U (NB-2D11 bound CaSR), 7E6T (TNCA bound CaSR).

The following data sets were generated
The following previously published data sets were used

Article and author information

Author details

  1. Xiaochen Chen

    The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-0426-9547
  2. Lu Wang

    The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
  3. Qianqian Cui

    The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
  4. Zhanyu Ding

    The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-8136-2243
  5. Li Han

    The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
  6. Yongjun Kou

    The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
  7. Wenqing Zhang

    The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
  8. Haonan Wang

    The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
  9. Xiaomin Jia

    The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
  10. Mei Dai

    The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
  11. Zhenzhong Shi

    The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
  12. Yuying Li

    The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
  13. Xiyang Li

    The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
  14. Yong Geng

    The CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
    For correspondence
    gengyong@simm.ac.cn
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-7144-3878

Funding

National Natural Science Foundation of China (No. 31670743)

  • Yong Geng

Shanghai Institute of Materia Medica, Chinese Academy of Sciences (5112345601)

  • Yong Geng

Shanghai Institute of Materia Medica, Chinese Academy of Sciences (2015123456005)

  • Yong Geng

National Natural Science Foundation of China (118180359901)

  • Yong Geng

Science and Technology Commission of Shanghai Municipality (No. 18JC1415400)

  • Yong Geng

Joint Research Fund for Overseas Chinese Scholars and Scholars in Hong Kong and Macao (No. 81628013)

  • Yong Geng

Natural Science Foundation of Shanghai (16ZR1442900)

  • Yong Geng

Shanghai Institute of Materia Medica, Chinese Academy of Sciences (CASIMM0120164013)

  • Yong Geng

Shanghai Institute of Materia Medica, Chinese Academy of Sciences (SIMM1606YZZ-06)

  • Yong Geng

Shanghai Institute of Materia Medica, Chinese Academy of Sciences (SIMM1601KF-06)

  • Yong Geng

Shanghai Institute of Materia Medica, Chinese Academy of Sciences (55201631121116101)

  • Yong Geng

Shanghai Institute of Materia Medica, Chinese Academy of Sciences (55201631121108000)

  • Yong Geng

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Ethics

Animal experimentation: The animal work was approved and under the supervision of Shanghai Institute of Materia Medica, Chinese Academy of Sciences (Permit Number: SYXK 2015-0027)

Reviewing Editor

  1. Randy B Stockbridge, University of Michigan, United States

Publication history

  1. Received: March 19, 2021
  2. Preprint posted: March 31, 2021 (view preprint)
  3. Accepted: August 31, 2021
  4. Accepted Manuscript published: September 1, 2021 (version 1)

Copyright

© 2021, Chen et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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