1. Structural Biology and Molecular Biophysics
  2. Cell Biology
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A mitofusin-dependent docking ring complex triggers mitochondrial fusion in vitro

  1. Tobias Brandt
  2. Laetitia Cavellini
  3. Werner Kühlbrandt
  4. Mickaël M Cohen  Is a corresponding author
  1. Max Planck Institute of Biophysics, Germany
  2. Sorbonne Universités, France
Research Article
  • Cited 52
  • Views 3,102
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Cite this article as: eLife 2016;5:e14618 doi: 10.7554/eLife.14618

Abstract

Fusion of mitochondrial outer membranes is crucial for proper organelle function and involves large GTPases called mitofusins. The discrete steps that allow mitochondria to attach to one another and merge their outer membranes are unknown. By combining an in vitro mitochondrial fusion assay with electron cryo-tomography (cryo-ET), we visualize the junction between attached mitochondria isolated from Saccharomyces cerevisiae and observe complexes that mediate this attachment. We find that cycles of GTP hydrolysis induce progressive formation of a docking ring structure around extended areas of contact. Further GTP hydrolysis triggers local outer membrane fusion at the periphery of the contact region. These findings unravel key features of mitofusin-dependent fusion of outer membranes and constitute an important advance in our understanding of how mitochondria connect and merge.

Article and author information

Author details

  1. Tobias Brandt

    Max Planck Institute of Biophysics, Frankfurt, Germany
    Competing interests
    No competing interests declared.
  2. Laetitia Cavellini

    Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Sorbonne Universités, Paris, France
    Competing interests
    No competing interests declared.
  3. Werner Kühlbrandt

    Max Planck Institute of Biophysics, Frankfurt, Germany
    Competing interests
    Werner Kühlbrandt, Reviewing editor, eLife.
  4. Mickaël M Cohen

    Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, Sorbonne Universités, Paris, France
    For correspondence
    cohen@ibpc.fr
    Competing interests
    No competing interests declared.

Reviewing Editor

  1. Nikolaus Pfanner, University of Freiburg, Germany

Publication history

  1. Received: January 21, 2016
  2. Accepted: June 1, 2016
  3. Accepted Manuscript published: June 2, 2016 (version 1)
  4. Version of Record published: June 30, 2016 (version 2)

Copyright

© 2016, Brandt 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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