1. Neuroscience
  2. Structural Biology and Molecular Biophysics
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Topography and motion of the acid-sensing ion channel intracellular domains

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Cite this article as: eLife 2021;10:e68955 doi: 10.7554/eLife.68955

Abstract

Acid-sensing ion channels (ASICs) are trimeric cation-selective channels activated by decreases in extracellular pH. The intracellular N and C terminal tails of ASIC1 influence channel gating, trafficking, and signaling in ischemic cell death. Despite several x-ray and cryo-EM structures of the extracellular and transmembrane segments of ASIC1, these important intracellular tails remain unresolved. Here we describe the coarse topography of the chicken ASIC1 intracellular domains determined by FRET, measured using either fluorescent lifetime imaging or patch clamp fluorometry. We find the C terminal tail projects into the cytosol by approximately 35 Å and that the N and C tail from the same subunits are closer than adjacent subunits. Using pH-insensitive fluorescent proteins, we fail to detect any relative movement between the N and C tails upon extracellular acidification but do observe axial motions of the membrane proximal segments towards the plasma membrane. Taken together, our study furnishes a coarse topographic map of the ASIC intracellular domains while providing directionality and context to intracellular conformational changes induced by extracellular acidification.

Data availability

All analyzed results contributing to this study are included in the manuscript and supporting files. Source data files have been provided for all figures containing data.

Article and author information

Author details

  1. Tyler Couch

    Department of Pharmacology and Physiology, University of Rochester, Rochester, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Kyle Berger

    Department of Pharmacology and Physiology, University of Rochester, Rochester, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Dana L Kneisley

    Department of Pharmacology and Physiology, University of Rochester, Rochester, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Tyler W McCullock

    Department of Pharmacology and Physiology, University of Rochester, Rochester, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-1628-1102
  5. Paul Kammermeier

    Department of Pharmacology and Physiology, University of Rochester, Rochester, United States
    Competing interests
    The authors declare that no competing interests exist.
  6. David M Maclean

    Department of Pharmacology and Physiology, University of Rochester, Rochester, United States
    For correspondence
    David_MacLean@urmc.rochester.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-8294-6075

Funding

National Institute of General Medical Sciences (R35GM137951)

  • David M Maclean

National Science Foundation

  • Tyler Couch

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

Reviewing Editor

  1. Leon D Islas, Universidad Nacional Autónoma de México, Mexico

Publication history

  1. Received: March 30, 2021
  2. Accepted: July 21, 2021
  3. Accepted Manuscript published: July 22, 2021 (version 1)

Copyright

© 2021, Couch 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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