Tim29 is a novel subunit of the human TIM22 translocase and is involved in complex assembly and stability

  1. Yilin Kang
  2. Michael James Baker
  3. Michael Liem
  4. Jade Louber
  5. Matthew McKenzie
  6. Ishara Atukorala
  7. Ching-Seng Ang
  8. Shivakumar Keerthikumar
  9. Suresh Mathivanan
  10. Diana Stojanovski  Is a corresponding author
  1. The University of Melbourne, Australia
  2. La Trobe University, Australia
  3. Hudson Institute of Medical Research, Australia

Abstract

The TIM22 complex mediates the import of hydrophobic carrier proteins into the mitochondrial inner membrane. While the TIM22 machinery has been well characterised in yeast, the human complex remains poorly characterised. Here, we identify Tim29 (C19orf52) as a novel, metazoan-specific subunit of the human TIM22 complex. The protein is integrated into the mitochondrial inner membrane with it's C-terminus exposed to the intermembrane space. Tim29 is required for the stability of the TIM22 complex and functions in the assembly of the hTim22. Furthermore, Tim29 contacts the Translocase of the Outer Mitochondrial Membrane, TOM complex, enabling a mechanism for transport of hydrophobic carrier substrates across the aqueous intermembrane space. Identification of Tim29 highlights the significance of analysing mitochondrial import systems across phylogenetic boundaries, which can reveal novel components and mechanisms in higher organisms.

Article and author information

Author details

  1. Yilin Kang

    Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Australia
    Competing interests
    The authors declare that no competing interests exist.
  2. Michael James Baker

    Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Australia
    Competing interests
    The authors declare that no competing interests exist.
  3. Michael Liem

    Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia
    Competing interests
    The authors declare that no competing interests exist.
  4. Jade Louber

    Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Australia
    Competing interests
    The authors declare that no competing interests exist.
  5. Matthew McKenzie

    Centre for Genetic Diseases, Hudson Institute of Medical Research, Melbourne, Australia
    Competing interests
    The authors declare that no competing interests exist.
  6. Ishara Atukorala

    Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia
    Competing interests
    The authors declare that no competing interests exist.
  7. Ching-Seng Ang

    The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Australia
    Competing interests
    The authors declare that no competing interests exist.
  8. Shivakumar Keerthikumar

    Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia
    Competing interests
    The authors declare that no competing interests exist.
  9. Suresh Mathivanan

    Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia
    Competing interests
    The authors declare that no competing interests exist.
  10. Diana Stojanovski

    Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Australia
    For correspondence
    d.stojanovski@unimelb.edu.au
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-0199-3222

Funding

The authors declare that there was no funding for this work

Reviewing Editor

  1. Nikolaus Pfanner, University of Freiburg, Germany

Publication history

  1. Received: May 4, 2016
  2. Accepted: August 14, 2016
  3. Accepted Manuscript published: August 24, 2016 (version 1)
  4. Version of Record published: September 8, 2016 (version 2)
  5. Version of Record updated: December 1, 2016 (version 3)

Copyright

© 2016, Kang 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

  • 2,294
    Page views
  • 514
    Downloads
  • 50
    Citations

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

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. Yilin Kang
  2. Michael James Baker
  3. Michael Liem
  4. Jade Louber
  5. Matthew McKenzie
  6. Ishara Atukorala
  7. Ching-Seng Ang
  8. Shivakumar Keerthikumar
  9. Suresh Mathivanan
  10. Diana Stojanovski
(2016)
Tim29 is a novel subunit of the human TIM22 translocase and is involved in complex assembly and stability
eLife 5:e17463.
https://doi.org/10.7554/eLife.17463
  1. Further reading

Further reading

    1. Biochemistry and Chemical Biology
    2. Cell Biology
    Andrea Volante, Juan Carlos Alonso, Kiyoshi Mizuuchi
    Research Article Updated

    Three-component ParABS partition systems ensure stable inheritance of many bacterial chromosomes and low-copy-number plasmids. ParA localizes to the nucleoid through its ATP-dependent nonspecific DNA-binding activity, whereas centromere-like parS-DNA and ParB form partition complexes that activate ParA-ATPase to drive the system dynamics. The essential parS sequence arrangements vary among ParABS systems, reflecting the architectural diversity of their partition complexes. Here, we focus on the pSM19035 plasmid partition system that uses a ParBpSM of the ribbon-helix-helix (RHH) family. We show that parSpSM with four or more contiguous ParBpSM-binding sequence repeats is required to assemble a stable ParApSM-ParBpSM complex and efficiently activate the ParApSM-ATPase, stimulating complex disassembly. Disruption of the contiguity of the parSpSM sequence array destabilizes the ParApSM-ParBpSM complex and prevents efficient ATPase activation. Our findings reveal the unique architecture of the pSM19035 partition complex and how it interacts with nucleoid-bound ParApSM-ATP.

    1. Biochemistry and Chemical Biology
    2. Structural Biology and Molecular Biophysics
    Chris Furlan, Nipa Chongdar ... James A Birrell
    Research Article Updated

    Electron bifurcation is a fundamental energy conservation mechanism in nature in which two electrons from an intermediate-potential electron donor are split so that one is sent along a high-potential pathway to a high-potential acceptor and the other is sent along a low-potential pathway to a low-potential acceptor. This process allows endergonic reactions to be driven by exergonic ones and is an alternative, less recognized, mechanism of energy coupling to the well-known chemiosmotic principle. The electron-bifurcating [FeFe] hydrogenase from Thermotoga maritima (HydABC) requires both NADH and ferredoxin to reduce protons generating hydrogen. The mechanism of electron bifurcation in HydABC remains enigmatic in spite of intense research efforts over the last few years. Structural information may provide the basis for a better understanding of spectroscopic and functional information. Here, we present a 2.3 Å electron cryo-microscopy structure of HydABC. The structure shows a heterododecamer composed of two independent ‘halves’ each made of two strongly interacting HydABC heterotrimers connected via a [4Fe–4S] cluster. A central electron transfer pathway connects the active sites for NADH oxidation and for proton reduction. We identified two conformations of a flexible iron–sulfur cluster domain: a ‘closed bridge’ and an ‘open bridge’ conformation, where a Zn2+ site may act as a ‘hinge’ allowing domain movement. Based on these structural revelations, we propose a possible mechanism of electron bifurcation in HydABC where the flavin mononucleotide serves a dual role as both the electron bifurcation center and as the NAD+ reduction/NADH oxidation site.