1. Neuroscience
  2. Structural Biology and Molecular Biophysics

Ca2+-dependent release of Synaptotagmin-1 from the SNARE complex on phosphatidylinositol 4,5-bisphosphate-containing membranes

  1. Rashmi Voleti
  2. Klaudia Jaczynska
  3. Josep Rizo  Is a corresponding author
  1. University of Texas Southwestern Medical Center, United States
https://doi.org/10.7554/eLife.57154
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  1. Rashmi Voleti
  2. Klaudia Jaczynska
  3. Josep Rizo
(2020)
Ca2+-dependent release of Synaptotagmin-1 from the SNARE complex on phosphatidylinositol 4,5-bisphosphate-containing membranes
eLife 9:e57154.
https://doi.org/10.7554/eLife.57154
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Abstract

The Ca2+ sensor synaptotagmin-1 and the SNARE complex cooperate to trigger neurotransmitter release. Structural studies elucidated three distinct synaptotagmin-1-SNARE complex binding modes involving polybasic, primary and tripartite interfaces of synaptotagmin-1. We investigated these interactions using NMR and fluorescence spectroscopy. Synaptotagmin-1 binds to the SNARE complex through the polybasic and primary interfaces in solution. Ca2+-free synaptotagmin-1 binds to SNARE complexes anchored on PIP2-containing nanodiscs. R398Q/R399Q and E295A/Y338W mutations at the primary interface, which strongly impair neurotransmitter release, disrupt and enhance synaptotagmin-1-SNARE complex binding, respectively. Ca2+ induces tight binding of synaptotagmin-1 to PIP2-containing nanodiscs, disrupting synaptotagmin-1-SNARE interactions. Specific effects of mutations in the polybasic region on Ca2+-dependent synaptotagmin-1-PIP2-membrane interactions correlate with their effects on release. Our data suggest that synaptotagmin-1 binds to the SNARE complex through the primary interface and that Ca2+ releases this interaction, inducing PIP2/membrane binding and allowing cooperation between synaptotagmin-1 and the SNAREs in membrane fusion to trigger release.

Data availability

The NMR data corresponding to Figs. 1-4 and corresponding figure supplements are publicly available at https://doi.org/10.5061/dryad.0zpc866vt. Source data are provided for all the FRET experiments shown in Figs. 5-9 and corresponding figure supplements.

The following data sets were generated

Article and author information

Author details

  1. Rashmi Voleti

    Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, United States
    Competing interests
    The authors declare that no competing interests exist.

  2. Klaudia Jaczynska

    Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, United States
    Competing interests
    The authors declare that no competing interests exist.

  3. Josep Rizo

    Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, United States
    For correspondence
    Jose.Rizo-Rey@UTSouthwestern.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-1773-8311

Funding

National Institute of Neurological Disorders and Stroke (R35 NS097333)

  • Josep Rizo

Welch Foundation (I-1304)

  • Josep Rizo

Howard Hughes Medical Institute

  • Rashmi Voleti

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

Reviewing Editor

  1. Nils Brose, Max Planck Institute of Experimental Medicine, Germany

Version history

  1. Received: March 23, 2020
  2. Accepted: August 12, 2020
  3. Accepted Manuscript published: August 18, 2020 (version 1)
  4. Version of Record published: September 17, 2020 (version 2)
  5. Version of Record updated: September 18, 2020 (version 3)

Copyright

© 2020, Voleti 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. Rashmi Voleti
  2. Klaudia Jaczynska
  3. Josep Rizo
(2020)
Ca2+-dependent release of Synaptotagmin-1 from the SNARE complex on phosphatidylinositol 4,5-bisphosphate-containing membranes
eLife 9:e57154.
https://doi.org/10.7554/eLife.57154

Share this article

https://doi.org/10.7554/eLife.57154

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