Independent evolution of functionally exchangeable mitochondrial outer membrane import complexes

• Main Authors: Daniela G Vitali, Sandro Käser, Antonia Kolb, Kai S Dimmer, Andre Schneider, Doron Rapaport
• Format: Article
• Language: English
• Published: eLife Sciences Publications Ltd 2018-06-01
• Series: eLife
• Subjects: mitochondria; trypanosome; outer membrane; MIM complex; biogenesis
• Online Access: https://elifesciences.org/articles/34488

Assembly and/or insertion of a subset of mitochondrial outer membrane (MOM) proteins, including subunits of the main MOM translocase, require the fungi-specific Mim1/Mim2 complex. So far it was unclear which proteins accomplish this task in other eukaryotes. Here, we show by reciprocal complementation that the MOM protein pATOM36 of trypanosomes is a functional analogue of yeast Mim1/Mim2 complex, even though these proteins show neither sequence nor topological similarity. Expression of pATOM36 rescues almost all growth, mitochondrial biogenesis, and morphology defects in yeast cells lacking Mim1 and/or Mim2. Conversely, co-expression of Mim1 and Mim2 restores the assembly and/or insertion defects of MOM proteins in trypanosomes ablated for pATOM36. Mim1/Mim2 and pATOM36 form native-like complexes when heterologously expressed, indicating that additional proteins are not part of these structures. Our findings indicate that Mim1/Mim2 and pATOM36 are the products of convergent evolution and arose only after the ancestors of fungi and trypanosomatids diverged.