Structure and physiological function of the human KCNQ1 channel voltage sensor intermediate state

  1. Keenan C Taylor
  2. Po Wei Kang
  3. Panpan Hou
  4. Nien-Du Yang
  5. Georg Kuenze
  6. Jarrod A Smith
  7. Jingyi Shi
  8. Hui Huang
  9. Kelli McFarland White
  10. Dungeng Peng
  11. Alfred L George
  12. Jens Meiler
  13. Robert L McFeeters
  14. Jianmin Cui
  15. Charles R Sanders  Is a corresponding author
  1. Vanderbilt University, United States
  2. Washington University in St Louis, United States
  3. Northwestern University, United States
  4. University of Alabama in Huntsville, United States

Abstract

Voltage-gated ion channels feature voltage sensor domains (VSDs) that exist in three distinct conformations during activation: resting, intermediate, and activated. Experimental determination of the structure of a potassium channel VSD in the intermediate state has previously proven elusive. Here, we report and validate the experimental three-dimensional structure of the human KCNQ1 voltage-gated potassium channel VSD in the intermediate state. We also used mutagenesis and electrophysiology in Xenopus laevis oocytes to functionally map the determinants of S4 helix motion during voltage-dependent transition from the intermediate to the activated state. Finally, the physiological relevance of the intermediate state KCNQ1 conductance is demonstrated using voltage-clamp fluorometry. This work illuminates the structure of the VSD intermediate state and demonstrates that intermediate state conductivity contributes to the unusual versatility of KCNQ1, which can function either as the slow delayed rectifier current (IKs) of the cardiac action potential or as a constitutively active epithelial leak current.

Data availability

The structures determined in this work have been deposited into the Protein Databank (PDB ID 6MIE).NMR data assignments and structural restraints have been deposited in the BioMagResBank (BMRB ID 30517).All electrophysiology and voltage-clamp fluorometry data generated or analysed during this study are included in the manuscript, supporting files, and source data file.

The following data sets were generated

Article and author information

Author details

  1. Keenan C Taylor

    Department of Biochemistry, Vanderbilt University, Nashville, United States
    Competing interests
    No competing interests declared.
  2. Po Wei Kang

    Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Diseases, Washington University in St Louis, St Louis, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-5933-545X
  3. Panpan Hou

    Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Diseases, Washington University in St Louis, St Louis, United States
    Competing interests
    No competing interests declared.
  4. Nien-Du Yang

    Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Diseases, Washington University in St Louis, St Louis, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-5261-7382
  5. Georg Kuenze

    Department of Biochemistry, Vanderbilt University, Nashville, United States
    Competing interests
    No competing interests declared.
  6. Jarrod A Smith

    Department of Biochemistry, Vanderbilt University, Nashville, United States
    Competing interests
    No competing interests declared.
  7. Jingyi Shi

    Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Diseases, Washington University in St Louis, St Louis, United States
    Competing interests
    Jingyi Shi, is the cofounder of a startup company VivoCor LLC, which is targeting IKs for the treatment of cardiac arrhythmia.
  8. Hui Huang

    Department of Biochemistry, Vanderbilt University, Nashville, United States
    Competing interests
    No competing interests declared.
  9. Kelli McFarland White

    Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Diseases, Washington University in St Louis, St Louis, United States
    Competing interests
    No competing interests declared.
  10. Dungeng Peng

    Department of Biochemistry, Vanderbilt University, Nashville, United States
    Competing interests
    No competing interests declared.
  11. Alfred L George

    Department of Pharmacology, Northwestern University, Chicago, United States
    Competing interests
    No competing interests declared.
  12. Jens Meiler

    Center for Structural Biology, Vanderbilt University, Nashville, United States
    Competing interests
    No competing interests declared.
  13. Robert L McFeeters

    Department of Chemistry, University of Alabama in Huntsville, Huntsville, United States
    Competing interests
    No competing interests declared.
  14. Jianmin Cui

    Department of Biomedical Engineering, Center for the Investigation of Membrane Excitability Diseases, Washington University in St Louis, St Louis, United States
    Competing interests
    Jianmin Cui, is the cofounder of a startup company VivoCor LLC, which is targeting IKs for the treatment of cardiac arrhythmia.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-9198-6332
  15. Charles R Sanders

    Department of Biochemistry, Vanderbilt University, Nashville, United States
    For correspondence
    chuck.sanders@vanderbilt.edu
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-2046-2862

Funding

National Institutes of Health (R01 HL122010)

  • Alfred L George
  • Jens Meiler
  • Charles R Sanders

National Institutes of Health (R01 NS092570)

  • Jianmin Cui

National Institutes of Health (R01 HL126774)

  • Jianmin Cui

National Institutes of Health (F32 GM117770)

  • Keenan C Taylor

American Heart Association (18POST34030203)

  • Panpan Hou

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

Reviewing Editor

  1. Merritt Maduke, Stanford University School of Medicine, United States

Ethics

Animal experimentation: Oocytes from Xenopus laevis (frogs) were employed in this work (at Washington University) and the frogs were cared for in accordance with the protocol approved by the Washington University Animal Studies Committee (Protocol # 20190030).

Version history

  1. Received: November 23, 2019
  2. Accepted: February 24, 2020
  3. Accepted Manuscript published: February 25, 2020 (version 1)
  4. Version of Record published: March 13, 2020 (version 2)

Copyright

© 2020, Taylor 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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  1. Keenan C Taylor
  2. Po Wei Kang
  3. Panpan Hou
  4. Nien-Du Yang
  5. Georg Kuenze
  6. Jarrod A Smith
  7. Jingyi Shi
  8. Hui Huang
  9. Kelli McFarland White
  10. Dungeng Peng
  11. Alfred L George
  12. Jens Meiler
  13. Robert L McFeeters
  14. Jianmin Cui
  15. Charles R Sanders
(2020)
Structure and physiological function of the human KCNQ1 channel voltage sensor intermediate state
eLife 9:e53901.
https://doi.org/10.7554/eLife.53901

Share this article

https://doi.org/10.7554/eLife.53901

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