Mia40 is a trans-site receptor that drives protein import into the mitochondrial intermembrane space by hydrophobic substrate binding

  1. Valentina Peleh
  2. Emmanuelle Cordat
  3. Johannes M Herrmann  Is a corresponding author
  1. University of Kaiserslautern, Germany
  2. University of Alberta, Canada

Abstract

Many proteins of the mitochondrial IMS contain conserved cysteines that are oxidized to disulfide bonds during their import. The conserved IMS protein Mia40 is essential for the oxidation and import of these proteins. Mia40 consists of two functional elements: an N-terminal cysteine-proline-cysteine motif conferring substrate oxidation, and a C-terminal hydrophobic pocket for substrate binding. In this study, we generated yeast mutants to dissect both Mia40 activities genetically and biochemically. Thereby we show that the substrate-binding domain of Mia40 is both necessary and sufficient to promote protein import, indicating that trapping by Mia40 drives protein translocation. An oxidase-deficient Mia40 mutant is inviable, but can be partially rescued by addition of the chemical oxidant diamide. Our results indicate that Mia40 predominantly serves as trans-site receptor of mitochondria that binds incoming proteins via hydrophobic interactions thereby mediating protein translocation across the outer membrane by a 'holding trap' rather than a 'folding trap' mechanism.

Article and author information

Author details

  1. Valentina Peleh

    Cell Biology, University of Kaiserslautern, Kaiserslautern, Germany
    Competing interests
    The authors declare that no competing interests exist.
  2. Emmanuelle Cordat

    Department of Physiology, University of Alberta, Edmonton, Canada
    Competing interests
    The authors declare that no competing interests exist.
  3. Johannes M Herrmann

    Cell Biology, University of Kaiserslautern, Kaiserslautern, Germany
    For correspondence
    hannes.herrmann@biologie.uni-kl.de
    Competing interests
    The authors declare that no competing interests exist.

Reviewing Editor

  1. Nikolaus Pfanner, University of Freiburg, Germany

Publication history

  1. Received: March 18, 2016
  2. Accepted: June 24, 2016
  3. Accepted Manuscript published: June 25, 2016 (version 1)
  4. Version of Record published: July 19, 2016 (version 2)

Copyright

© 2016, Peleh 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. Valentina Peleh
  2. Emmanuelle Cordat
  3. Johannes M Herrmann
(2016)
Mia40 is a trans-site receptor that drives protein import into the mitochondrial intermembrane space by hydrophobic substrate binding
eLife 5:e16177.
https://doi.org/10.7554/eLife.16177

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