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Author Spotlight: Oxygen-Independent Assays to Measure Mitochondrial Function in Mammals
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Independent evolution of functionally exchangeable mitochondrial outer membrane import complexes

Daniela G Vitali1, Sandro Käser2, Antonia Kolb1

  • 1Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany.

Elife
|June 21, 2018
PubMed

Insights

The fungi-specific Mim1/Mim2 complex and trypanosome pATOM36 protein are functional analogs for mitochondrial outer membrane protein insertion. These proteins evolved convergently in distinct eukaryotic lineages.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Evolutionary Biology

Background:

  • Mitochondrial outer membrane (MOM) protein assembly is crucial for organelle function.
  • The fungi-specific Mim1/Mim2 complex mediates the insertion of key MOM proteins.
  • The functional equivalents of Mim1/Mim2 in other eukaryotes remained unknown.

Purpose of the Study:

  • To identify and characterize the functional analogue of the Mim1/Mim2 complex in trypanosomes.
  • To investigate the evolutionary origins of MOM protein insertion machinery.

Main Methods:

  • Reciprocal genetic complementation experiments between yeast and trypanosomes.
  • Analysis of protein complex formation via heterologous expression.
  • Assessment of mitochondrial biogenesis, morphology, and protein assembly defects.

Main Results:

  • Trypanosome MOM protein pATOM36 functionally complements yeast Mim1/Mim2 deletion mutants.
  • Yeast Mim1/Mim2 complex rescues MOM protein assembly defects in pATOM36-deficient trypanosomes.
  • pATOM36 and Mim1/Mim2 form stable complexes independently of other proteins.

Conclusions:

  • pATOM36 is the functional analogue of the yeast Mim1/Mim2 complex in trypanosomes.
  • These proteins represent a case of convergent evolution, arising independently after the divergence of fungi and trypanosomatids.
Keywords:
MIM complexS. cerevisiaebiochemistrybiogenesischemical biologymitochondriaouter membranetrypanosome

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