Mitochondrial preprotein translocase of trypanosomatids has a bacterial origin

Pusnik, Mascha; Schmidt, Oliver; Perry, Andrew J.; Oeljeklaus, Silke; Niemann, Moritz; Warscheid, Bettina; Lithgow, Trevor; Meisinger, Chris; Schneider, André (2011). Mitochondrial preprotein translocase of trypanosomatids has a bacterial origin. Current Biology, 21(20), pp. 1738-1743. Cambridge, Mass.: Cell Press 10.1016/j.cub.2011.08.060

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Mitochondria are found in all eukaryotic cells and derive from a bacterial endosymbiont [1, 2]. The evolution of a protein import system was a prerequisite for the conversion of the endosymbiont into a true organelle. Tom40, the essential component of the protein translocase of the outer membrane, is conserved in mitochondria of almost all eukaryotes but lacks bacterial orthologs [3-6]. It serves as the gateway through which all mitochondrial proteins are imported. The parasitic protozoa Trypanosoma brucei and its relatives do not have a Tom40-like protein, which raises the question of how proteins are imported by their mitochondria [7, 8]. Using a combination of bioinformatics and in vivo and in vitro studies, we have discovered that T. brucei likely employs a different import channel, termed ATOM (archaic translocase of the outer mitochondria! membrane). ATOM mediates the import of nuclear-encoded proteins into mitochondria and is essential for viability of trypanosomes. It is not related to Tom40 but is instead an ortholog of a subgroup of the 0mp85 protein superfamily that is involved in membrane translocation and insertion of bacterial outer membrane proteins [9]. This suggests that the protein import channel in trypanosomes is a relic of an archaic protein transport system that was operational in the ancestor of all eukaryotes.

Item Type:

Journal Article (Original Article)


08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP)

UniBE Contributor:

Schneider, André




Cell Press




Factscience Import

Date Deposited:

04 Oct 2013 14:26

Last Modified:

07 Jan 2016 15:55

Publisher DOI:


Web of Science ID:


URI: (FactScience: 214981)

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