1. Cell Biology
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A novel mode of Capping Protein-regulation by Twinfilin

  1. Adam B Johnston
  2. Denise M Hilton
  3. Patrick McConnell
  4. Britney Johnson
  5. Meghan T Harris
  6. Avital Simone
  7. Gaya K Amarasinghe
  8. John A Cooper
  9. Bruce L Goode  Is a corresponding author
  1. Brandeis University, United States
  2. Washington University in St Louis, United States
Research Article
  • Cited 15
  • Views 2,035
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Cite this article as: eLife 2018;7:e41313 doi: 10.7554/eLife.41313

Abstract

Cellular actin assembly is controlled at the barbed ends of actin filaments, where capping protein (CP) limits polymerization. Twinfilin is a conserved in vivo binding partner of CP, yet the significance of this interaction has remained a mystery. Here, we discover that the C-terminal tail of Twinfilin harbors a CP-interacting (CPI) motif, identifying it as a novel CPI-motif protein. Twinfilin and the CPI-motif protein CARMIL have overlapping binding sites on CP. Further, Twinfilin binds competitively with CARMIL to CP, protecting CP from barbed-end displacement by CARMIL. Twinfilin also accelerates dissociation of the CP inhibitor V-1, restoring CP to an active capping state. Knockdowns of Twinfilin and CP each cause similar defects in cell morphology, and elevated Twinfilin expression rescues defects caused by CARMIL hyperactivity. Together, these observations define Twinfilin as the first 'pro-capping' ligand of CP and lead us to propose important revisions to our understanding of the CP regulatory cycle.

Data availability

All datasets associated with this article are included in the manuscript and supporting files.

Article and author information

Author details

  1. Adam B Johnston

    Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Denise M Hilton

    Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-1577-1855
  3. Patrick McConnell

    Department of Biochemistry and Molecular Biophysics, Washington University in St Louis, St Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Britney Johnson

    Department of Pathology and Immunology, Washington University in St Louis, St Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Meghan T Harris

    Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, United States
    Competing interests
    The authors declare that no competing interests exist.
  6. Avital Simone

    Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, United States
    Competing interests
    The authors declare that no competing interests exist.
  7. Gaya K Amarasinghe

    Department of Pathology and Immunology, Washington University in St Louis, St Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
  8. John A Cooper

    Department of Biochemistry and Molecular Biophysics, Washington University in St Louis, St Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-0933-4571
  9. Bruce L Goode

    Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, United States
    For correspondence
    goode@brandeis.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-6443-5893

Funding

National Institutes of Health (R01 GM063691)

  • Bruce L Goode

Defense Threat Reduction Agency (HDTRA1-16-1-0033)

  • Gaya K Amarasinghe

National Institutes of Health (R35 GM118171)

  • John A Cooper

National Science Foundation (MRSEC DMR-1420382)

  • Bruce L Goode

National Institutes of Health (P01 AI120943)

  • Gaya K Amarasinghe

National Institutes of Health (R01 AI123926)

  • Gaya K Amarasinghe

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

Reviewing Editor

  1. Anna Akhmanova, Utrecht University, Netherlands

Publication history

  1. Received: August 21, 2018
  2. Accepted: October 22, 2018
  3. Accepted Manuscript published: October 23, 2018 (version 1)
  4. Version of Record published: November 21, 2018 (version 2)

Copyright

© 2018, Johnston 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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