Shaping the import system of mitochondria
Mitochondria are organelles that fulfil a variety of critical functions in eukaryotic cells. The vast majority of mitochondrial proteins are made in the cytosol, and then imported into the organelle. These proteins are recognized and processed by various import machineries, which are embedded in the two membranes (inner and outer mitochondrial membranes) that enclose a mitochondrion.
Assembly and/or insertion of a subset of mitochondrial outer membrane proteins require the fungi-specific Mim1/Mim2 complex. So far it was unclear which proteins accomplish this task in other eukaryotes. In collaboration with investigators from Bern University, IFIB researchers have shown 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. These findings indicate that Mim1/Mim2 and pATOM36 are the products of convergent evolution and arose only after the ancestors of fungi and trypanosomatids diverged.
Daniela Vitali, Sandro Käser, Antonia Kolb, Kai S Dimmer, Andre Schneider, Doron Rapaport: Independent evolution of functionally exchangeable mitochondrial outer membrane import complexes. eLife, 2018;7:e34488. DOI: https://doi.org/10.7554/eLife.34488
Prof. Doron Rapaport, PhD
Interfaculty Institute of Biochemistry
University of Tuebingen