title: Outer membrane protein functions as integrator of protein import and DNA inheritance in mitochondria.
abstract: Trypanosomatids are one of the earliest diverging eukaryotes that have fully functional mitochondria. pATOM36 is a trypanosomatid-specific essential mitochondrial outer membrane protein that has been implicated in protein import. Changes in the mitochondrial proteome induced by ablation of pATOM36 and in vitro assays show that pATOM36 is required for the assembly of the archaic translocase of the outer membrane (ATOM), the functional analog of the TOM complex in other organisms. Reciprocal pull-down experiments and immunofluorescence analyses demonstrate that a fraction of pATOM36 interacts and colocalizes with TAC65, a previously uncharacterized essential component of the tripartite attachment complex (TAC). The TAC links the single-unit mitochondrial genome to the basal body of the flagellum and mediates the segregation of the replicated mitochondrial genomes. RNAi experiments show that pATOM36, in line with its dual localization, is not only essential for ATOM complex assembly but also for segregation of the replicated mitochondrial genomes. However, the two functions are distinct, as a truncated version of pATOM36 lacking the 75 C-terminal amino acids can rescue kinetoplast DNA missegregation but not the lack of ATOM complex assembly. Thus, pATOM36 has a dual function and integrates mitochondrial protein import with mitochondrial DNA inheritance.
authors.affiliation: Department of Chemistry and Biochemistry, University of Bern, Bern CH-3012, Switzerland;
authors.forename: Sandro
authors.initials: S
authors.lastname: Käser
authors.affiliation: Department of Biochemistry and Functional Proteomics, Faculty of Biology, University of Freiburg, Freiburg 79104, Germany;
authors.forename: Silke
authors.initials: S
authors.lastname: Oeljeklaus
authors.affiliation: Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom;
authors.forename: Jiří
authors.initials: J
authors.lastname: Týč
authors.affiliation: Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, United Kingdom;
authors.forename: Sue
authors.initials: S
authors.lastname: Vaughan
authors.affiliation: Department of Biochemistry and Functional Proteomics, Faculty of Biology, University of Freiburg, Freiburg 79104, Germany; Centre for Biological Signalling Studies (BIOSS), University of Freiburg, Freiburg 79104, Germany andre.schneider@dcb.unibe.ch Bettina.warscheid@biologie.uni-freiburg.de.
authors.forename: Bettina
authors.initials: B
authors.lastname: Warscheid
authors.affiliation: Department of Chemistry and Biochemistry, University of Bern, Bern CH-3012, Switzerland; andre.schneider@dcb.unibe.ch Bettina.warscheid@biologie.uni-freiburg.de.
authors.forename: André
authors.initials: A
authors.lastname: Schneider
mesh_terms: D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D004272:DNA, Mitochondrial / Q000235:genetics / Q000378:metabolism*; D016054:DNA, Protozoan / Q000235:genetics / Q000378:metabolism; D005407:Flagella / Q000378:metabolism; D054629:Genome, Mitochondrial / Q000235:genetics; D033681:Mitochondrial Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport / Q000235:genetics; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D017386:Sequence Homology, Amino Acid; D014346:Trypanosoma brucei brucei / Q000166:cytology / Q000235:genetics / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D004272:DNA, Mitochondrial; D016054:DNA, Protozoan; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D024101:Mitochondrial Proteins; D015800:Protozoan Proteins
keywords: evolution; mitochondria; mitochondrial genome; protein import; trypanosomes