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

Elife. 2016 Aug 24:5:e17463. doi: 10.7554/eLife.17463.


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 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.

Keywords: TIM22; biochemistry; cell biology; human; mitochondria; protein trafficking.

MeSH terms

  • Cell Line
  • Humans
  • Mitochondrial Membrane Transport Proteins / analysis*
  • Mitochondrial Membranes / enzymology*
  • Mitochondrial Precursor Protein Import Complex Proteins
  • Protein Multimerization
  • Protein Subunits / analysis*


  • Mitochondrial Membrane Transport Proteins
  • Mitochondrial Precursor Protein Import Complex Proteins
  • Protein Subunits
  • TIMM29 protein, human

Grants and funding

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication