What can a unicellular parasite tell us about mitochondrial biogenesis?

Schneider, André (12 October 2015). What can a unicellular parasite tell us about mitochondrial biogenesis? (Unpublished). In: FEBS/EMBO course: Mitochondria in life, death and disease. Fodeles, Kreta, Griechenland. 12.-16.10.2015.

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In the unicellular parasite Trypanosoma brucei, as in other eukaryotes, more than 95% of all mitochondrial proteins are imported from the cytosol. The recently characterized multisubunit ATOM complex, the functional analogue of the TOM complex of yeast, mediates import of essentially all proteins across the outer mitochondrial membrane in T. brucei. Moreover, an additional protein termed pATOM36, which is loosely associated with the ATOM complex, has been implicated in the import of only a subset of mitochondrial proteins. Here we have investigated more precisely which role pATOM36 plays in mitochondrial protein import. RNAi mediated ablation of pATOM36 specifically depletes a subset of outer mitochondrial membrane proteins including ATOM complex subunits and as a consequence results in the collapse of the ATOM complex as shown by Blue native PAGE. In addition, a SILAC-based global proteomic analysis of uninduced and induced pATOM36 RNAi cells together with in vitro import experiments suggest that pATOM36 might be a novel protein import factor acting on a subset of alpha-helically anchored mitochondrial outer membrane proteins. Identification of pATOM36 interaction partners by co-immunoprecipitation together with immunofluorescence analysis shows that unexpectedly a fraction of the protein is associated with the tripartite attachment complex (TAC). This complex is essential for proper inheritance of the mitochondrial DNA in T. brucei. It forms a physical connection between the single unit mitochondrial DNA and the basal body of the flagellum that is stable throughout the cell cycle.
Thus, pATOM36 simultaneously mediates ATOM assembly, and thus protein import, as well as mitochondrial DNA inheritance since it is an essential component of the TAC.

Item Type:	Conference or Workshop Item (Paper)
Division/Institute:	08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP)
UniBE Contributor:	Schneider, André
Subjects:	500 Science > 570 Life sciences; biology 500 Science > 540 Chemistry
Language:	English
Submitter:	Christina Schüpbach
Date Deposited:	28 Jan 2016 15:14
Last Modified:	05 Dec 2022 14:51
URI:	https://boris.unibe.ch/id/eprint/74806