title: Mitochondrial translation factors of Trypanosoma brucei: elongation factor-Tu has a unique subdomain that is essential for its function.
abstract: Mitochondrial translation in the parasitic protozoan Trypanosoma brucei relies on imported eukaryotic-type tRNAs as well as on bacterial-type ribosomes that have the shortest known rRNAs. Here we have identified the mitochondrial translation elongation factors EF-Tu, EF-Ts, EF-G1 and release factor RF1 of trypanosomatids and show that their ablation impairs growth and oxidative phosphorylation. In vivo labelling experiments and a SILAC-based analysis of the global proteomic changes induced by EF-Tu RNAi directly link EF-Tu to mitochondrial translation. Moreover, EF-Tu RNAi reveals downregulation of many nuclear encoded subunits of cytochrome oxidase as well as of components of the bc1-complex, whereas most cytosolic ribosomal proteins were upregulated. Interestingly, T. brucei EF-Tu has a 30-amino-acid-long, highly charged subdomain, which is unique to trypanosomatids. A combination of RNAi and complementation experiments shows that this subdomain is essential for EF-Tu function, but that it can be replaced by a similar sequence found in eukaryotic EF-1a, the cytosolic counterpart of EF-Tu. A recent cryo-electron microscopy study revealed that trypanosomatid mitochondrial ribosomes have a unique intersubunit space that likely harbours the EF-Tu binding site. These findings suggest that the trypanosomatid-specific EF-Tu subdomain serves as an adaption for binding to these unusual mitochondrial ribosomes.
authors.affiliation: Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012, Bern, Switzerland.
authors.forename: Marina
authors.initials: M
authors.lastname: Cristodero
authors.forename: Jan
authors.initials: J
authors.lastname: Mani
authors.forename: Silke
authors.initials: S
authors.lastname: Oeljeklaus
authors.forename: Lukas
authors.initials: L
authors.lastname: Aeberhard
authors.forename: Hassan
authors.initials: H
authors.lastname: Hashimi
authors.forename: David J F
authors.initials: DJ
authors.lastname: Ramrath
authors.forename: Julius
authors.initials: J
authors.lastname: Lukeš
authors.forename: Bettina
authors.initials: B
authors.lastname: Warscheid
authors.forename: André
authors.initials: A
authors.lastname: Schneider
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D002460:Cell Line; D003576:Electron Transport Complex IV / Q000378:metabolism; D005786:Gene Expression Regulation; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000737:chemistry* / Q000502:physiology; D008969:Molecular Sequence Data; D009154:Mutation; D010085:Oxidative Phosphorylation; D020653:Peptide Elongation Factor G / Q000235:genetics / Q000378:metabolism; D010444:Peptide Elongation Factor Tu / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D010445:Peptide Elongation Factors / Q000235:genetics / Q000378:metabolism; D010454:Peptide Termination Factors / Q000235:genetics / Q000378:metabolism; D040901:Proteomics; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D034622:RNA Interference; D012270:Ribosomes / Q000378:metabolism*; D016415:Sequence Alignment; D014346:Trypanosoma brucei brucei / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*
chemical_list: D024101:Mitochondrial Proteins; D020653:Peptide Elongation Factor G; D010445:Peptide Elongation Factors; D010454:Peptide Termination Factors; D015800:Protozoan Proteins; C023512:elongation factor Ts; D003576:Electron Transport Complex IV; D010444:Peptide Elongation Factor Tu