1. Biochemistry and Chemical Biology
  2. Cell Biology
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Protein translocation channel of mitochondrial inner membrane and matrix-exposed import motor communicate via two-domain coupling protein

  1. Rupa Banerjee
  2. Christina Gladkova
  3. Koyeli Mapa
  4. Gregor Witte
  5. Dejana Mokranjac  Is a corresponding author
  1. Ludwig-Maximilians-Universität, Germany
Research Article
  • Cited 27
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Cite this article as: eLife 2015;4:e11897 doi: 10.7554/eLife.11897

Abstract

The majority of mitochondrial proteins are targeted to mitochondria by N-terminal presequences and use the TIM23 complex for their translocation across the mitochondrial inner membrane. During import, translocation through the channel in the inner membrane is coupled to the ATP-dependent action of an Hsp70-based import motor at the matrix face. How these two processes are coordinated remained unclear. We show here that the two domain structure of Tim44 plays a central role in this process. The N-terminal domain of Tim44 interacts with the components of the import motor whereas its C-terminal domain interacts with the translocation channel and is in contact with translocating proteins. Our data suggest that the translocation channel and the import motor of the TIM23 complex communicate through rearrangements of the two domains of Tim44 that are stimulated by translocating proteins.

Article and author information

Author details

  1. Rupa Banerjee

    Biomedical Center Munich, Department of Physiological Chemistry, Ludwig-Maximilians-Universität, Munich, Germany
    Competing interests
    The authors declare that no competing interests exist.
  2. Christina Gladkova

    Biomedical Center Munich, Department of Physiological Chemistry, Ludwig-Maximilians-Universität, Munich, Germany
    Competing interests
    The authors declare that no competing interests exist.
  3. Koyeli Mapa

    Biomedical Center Munich, Department of Physiological Chemistry, Ludwig-Maximilians-Universität, Munich, Germany
    Competing interests
    The authors declare that no competing interests exist.
  4. Gregor Witte

    Gene Center, Department of Biochemistry, Ludwig-Maximilians-Universität, Munich, Germany
    Competing interests
    The authors declare that no competing interests exist.
  5. Dejana Mokranjac

    Biomedical Center Munich, Department of Physiological Chemistry, Ludwig-Maximilians-Universität, Munich, Germany
    For correspondence
    dejana.mokranjac@med.uni-muenchen.de
    Competing interests
    The authors declare that no competing interests exist.

Reviewing Editor

  1. Nikolaus Pfanner, Univ. of Freiburg, Germany

Publication history

  1. Received: September 26, 2015
  2. Accepted: December 28, 2015
  3. Accepted Manuscript published: December 29, 2015 (version 1)
  4. Version of Record published: February 1, 2016 (version 2)

Copyright

© 2015, Banerjee 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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