v-SNARE transmembrane domains function as catalysts for vesicle fusion

  1. Madhurima Dhara
  2. Antonio Yarzagaray
  3. Mazen Makke
  4. Barbara Schindeldecker
  5. Yvonne Schwarz
  6. Ahmed Shaaban
  7. Satyan Sharma
  8. Rainer A Böckmann
  9. Manfred Lindau
  10. Ralf Mohrmann
  11. Dieter Bruns  Is a corresponding author
  1. Saarland University, Germany
  2. Max-Planck-Institute for Biophysical Chemistry, Germany
  3. Friedrich-Alexander University, Germany

Abstract

Vesicle fusion is mediated by assembly of SNARE proteins between opposing membranes, but it is unknown whether transmembrane domains (TMDs) of SNARE proteins serve mechanistic functions that go beyond passive anchoring of the force-generating SNAREpin to the fusing membranes. Here, we show that conformational flexibility of synaptobrevin-2 TMD is essential for efficient Ca2+-triggered exocytosis and actively promotes membrane fusion as well as fusion pore expansion. Specifically, introduction of helix-stabilizing leucine residues within the TMD region spanning the vesicle's outer leaflet strongly impairs exocytosis and decelerates fusion pore dilation. In contrast, increasing the number of helix-destabilizing, ß-branched valine or isoleucine residues within the TMD restores normal secretion but accelerates fusion pore expansion beyond the rate found for the wildtype protein. These observations provide evidence that the synaptobrevin-2 TMD catalyzes the fusion process by its structural flexibility, actively setting the pace of fusion pore expansion.

Article and author information

Author details

  1. Madhurima Dhara

    Institute for Physiology, Saarland University, Homburg, Germany
    Competing interests
    The authors declare that no competing interests exist.
  2. Antonio Yarzagaray

    Institute for Physiology, Saarland University, Homburg, Germany
    Competing interests
    The authors declare that no competing interests exist.
  3. Mazen Makke

    Institute for Physiology, Saarland University, Homburg, Germany
    Competing interests
    The authors declare that no competing interests exist.
  4. Barbara Schindeldecker

    Institute for Physiology, Saarland University, Homburg, Germany
    Competing interests
    The authors declare that no competing interests exist.
  5. Yvonne Schwarz

    Institute for Physiology, Saarland University, Homburg, Germany
    Competing interests
    The authors declare that no competing interests exist.
  6. Ahmed Shaaban

    Zentrum für Human- und Molekularbiologie, Saarland University, Homburg, Germany
    Competing interests
    The authors declare that no competing interests exist.
  7. Satyan Sharma

    Group Nanoscale Cell Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
    Competing interests
    The authors declare that no competing interests exist.
  8. Rainer A Böckmann

    Computational Biology, Friedrich-Alexander University, Erlangen, Germany
    Competing interests
    The authors declare that no competing interests exist.
  9. Manfred Lindau

    Group Nanoscale Cell Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
    Competing interests
    The authors declare that no competing interests exist.
  10. Ralf Mohrmann

    Zentrum für Human- und Molekularbiologie, Saarland University, Homburg, Germany
    Competing interests
    The authors declare that no competing interests exist.
  11. Dieter Bruns

    Institute for Physiology, Saarland University, Homburg, Germany
    For correspondence
    dieter.bruns@uks.eu
    Competing interests
    The authors declare that no competing interests exist.

Reviewing Editor

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

Version history

  1. Received: May 5, 2016
  2. Accepted: June 24, 2016
  3. Accepted Manuscript published: June 25, 2016 (version 1)
  4. Version of Record published: August 3, 2016 (version 2)

Copyright

© 2016, Dhara 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.

Metrics

  • 3,991
    Page views
  • 668
    Downloads
  • 40
    Citations

Article citation count generated by polling the highest count across the following sources: Crossref, PubMed Central, Scopus.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Open citations (links to open the citations from this article in various online reference manager services)

Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)

  1. Madhurima Dhara
  2. Antonio Yarzagaray
  3. Mazen Makke
  4. Barbara Schindeldecker
  5. Yvonne Schwarz
  6. Ahmed Shaaban
  7. Satyan Sharma
  8. Rainer A Böckmann
  9. Manfred Lindau
  10. Ralf Mohrmann
  11. Dieter Bruns
(2016)
v-SNARE transmembrane domains function as catalysts for vesicle fusion
eLife 5:e17571.
https://doi.org/10.7554/eLife.17571

Share this article

https://doi.org/10.7554/eLife.17571

Further reading

    1. Developmental Biology
    2. Neuroscience
    Wen Wang, Xiao Zhang ... Zi-Bing Jin
    Research Article Updated

    Chimeric RNAs have been found in both cancerous and healthy human cells. They have regulatory effects on human stem/progenitor cell differentiation, stemness maintenance, and central nervous system development. However, whether they are present in human retinal cells and their physiological functions in the retinal development remain unknown. Based on the human embryonic stem cell-derived retinal organoids (ROs) spanning from days 0 to 120, we present the expression atlas of chimeric RNAs throughout the developing ROs. We confirmed the existence of some common chimeric RNAs and also discovered many novel chimeric RNAs during retinal development. We focused on CTNNBIP1-CLSTN1 (CTCL) whose downregulation caused precocious neuronal differentiation and a marked reduction of neural progenitors in human cerebral organoids. CTCL is universally present in human retinas, ROs, and retinal cell lines, and its loss-of-function biases the progenitor cells toward retinal pigment epithelial cell fate at the expense of retinal cells. Together, this work provides a landscape of chimeric RNAs and reveals evidence for their critical role in human retinal development.

    1. Neuroscience
    Peibo Xu, Jian Peng ... Yuejun Chen
    Research Article

    Deciphering patterns of connectivity between neurons in the brain is a critical step toward understanding brain function. Imaging-based neuroanatomical tracing identifies area-to-area or sparse neuron-to-neuron connectivity patterns, but with limited throughput. Barcode-based connectomics maps large numbers of single-neuron projections, but remains a challenge for jointly analyzing single-cell transcriptomics. Here, we established a rAAV2-retro barcode-based multiplexed tracing method that simultaneously characterizes the projectome and transcriptome at the single neuron level. We uncovered dedicated and collateral projection patterns of ventromedial prefrontal cortex (vmPFC) neurons to five downstream targets and found that projection-defined vmPFC neurons are molecularly heterogeneous. We identified transcriptional signatures of projection-specific vmPFC neurons, and verified Pou3f1 as a marker gene enriched in neurons projecting to the lateral hypothalamus, denoting a distinct subset with collateral projections to both dorsomedial striatum and lateral hypothalamus. In summary, we have developed a new multiplexed technique whose paired connectome and gene expression data can help reveal organizational principles that form neural circuits and process information.