Abstract

ComplexinII (CpxII) inhibits non-synchronized vesicle fusion, but the underlying mechanisms have remained unclear. Here, we provide evidence that the far C-terminal domain (CTD) of CpxII interferes with SNARE assembly, thereby arresting tonic exocytosis. Acute infusion of a CTD-derived peptide into mouse chromaffin cells enhances synchronous release by diminishing premature vesicle fusion like full-length CpxII, indicating a direct, inhibitory function of the CTD that sets the magnitude of the primed vesicle pool. We describe a high degree of structural similarity between the CpxII CTD and the SNAP25-SN1 domain (C-terminal half) and show that the CTD peptide lowers the rate of SDS-resistant SNARE complex formation in vitro. Moreover, corresponding CpxII:SNAP25 chimeras do restore complexin's function and even 'superclamp' tonic secretion. Collectively, these results support a so far unrecognized clamping mechanism wherein the CpxII C-terminus hinders spontaneous SNARE complex assembly, enabling the build-up of a release-ready pool of vesicles for synchronized Ca2+-triggered exocytosis.

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All data generated or analysed during this study are included in the manuscript and supporting files.

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Author details

  1. Mazen Makke

    Institute for Physiology, Center of Integrative Physiology and Molecular Medicine, University of Saarland, Homburg, Germany
    Competing interests
    The authors declare that no competing interests exist.
  2. Maria Mantero Martinez

    Institute for Physiology, Center of Integrative Physiology and Molecular Medicine, University of Saarland, Homburg, Germany
    Competing interests
    The authors declare that no competing interests exist.
  3. Surya Gaya

    Institute for Physiology, Center of Integrative Physiology and Molecular Medicine, University of Saarland, Homburg, Germany
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-0163-5748
  4. Yvonne Schwarz

    Institute for Physiology, Center of Integrative Physiology and Molecular Medicine, University of Saarland, Homburg, Germany
    Competing interests
    The authors declare that no competing interests exist.
  5. Walentina Frisch

    Institute for Physiology, Center of Integrative Physiology and Molecular Medicine, University of Saarland, Homburg, Germany
    Competing interests
    The authors declare that no competing interests exist.
  6. Lina Silva-Bermudez

    Institute for Physiology, Center of Integrative Physiology and Molecular Medicine, University of Saarland, Homburg, Germany
    Competing interests
    The authors declare that no competing interests exist.
  7. Martin Jung

    Institute for Medical Biochemistry and Molecular Biology, University of Saarland, Homburg, Germany
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-1482-7020
  8. Ralf Mohrmann

    Institute of Physiology, Otto-von-Guericke University, Magdeburg, Germany
    Competing interests
    The authors declare that no competing interests exist.
  9. Madhurima Dhara

    Institute for Physiology, Center of Integrative Physiology and Molecular Medicine, University of Saarland, Homburg, Germany
    For correspondence
    madhurima.dhara@uks.eu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-7745-472X
  10. Dieter Bruns

    Institute for Physiology, Center of Integrative Physiology and Molecular Medicine, University of Saarland, Homburg, Germany
    For correspondence
    dieter.bruns@uks.eu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-2497-1878

Funding

Deutsche Forschungsgemeinschaft (SFB894)

  • Martin Jung
  • Dieter Bruns

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

Reviewing Editor

  1. Reinhard Jahn, Max Planck Institute for Biophysical Chemistry, Germany

Version history

  1. Received: June 6, 2018
  2. Accepted: July 24, 2018
  3. Accepted Manuscript published: July 25, 2018 (version 1)
  4. Version of Record published: August 3, 2018 (version 2)

Copyright

© 2018, Makke 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. Mazen Makke
  2. Maria Mantero Martinez
  3. Surya Gaya
  4. Yvonne Schwarz
  5. Walentina Frisch
  6. Lina Silva-Bermudez
  7. Martin Jung
  8. Ralf Mohrmann
  9. Madhurima Dhara
  10. Dieter Bruns
(2018)
A mechanism for exocytotic arrest by the Complexin C-terminus
eLife 7:e38981.
https://doi.org/10.7554/eLife.38981

Share this article

https://doi.org/10.7554/eLife.38981

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