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

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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.

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Yilin Kang

Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Australia

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The authors declare that no competing interests exist.
Michael James Baker

Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Australia

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The authors declare that no competing interests exist.
Michael Liem

Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia

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The authors declare that no competing interests exist.
Jade Louber

Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Australia

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The authors declare that no competing interests exist.
Matthew McKenzie

Centre for Genetic Diseases, Hudson Institute of Medical Research, Melbourne, Australia

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The authors declare that no competing interests exist.
Ishara Atukorala

Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia

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Ching-Seng Ang

The Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Australia

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Shivakumar Keerthikumar

Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia

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Suresh Mathivanan

Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia

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Diana Stojanovski

Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, Australia

For correspondence
d.stojanovski@unimelb.edu.au

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The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0002-0199-3222

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The authors declare that there was no funding for this work

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