title: Trypanosoma brucei has a canonical mitochondrial processing peptidase.
abstract: Most mitochondrial matrix and inner membrane proteins have N-terminal presequences which serve as import signals. After import these presequences are cleaved by the heterodimeric mitochondrial processing peptidase. In the parasitic protozoa Trypanosoma brucei mitochondrial protein import relies on presequences that are much shorter than in other eukaryotes. How they are processed is unknown. The trypansomal genome encodes four open reading frames that are annotated as mitochondrial processing peptidase. Here we show that RNAi-mediated ablation of two of these proteins leads to a growth arrest and a concomitant accumulation of mitochondrial precursor proteins inside mitochondria. Import experiments using isolated mitochondria from RNAi cell lines reveals that both proteins are required for efficient import and processing of the tested precursor protein. Reciprocal immunoprecipitation demonstrates that the proteins interact with each other. In summary these results show that we have identified the two subunits of the trypanosomal mitochondrial processing peptidase.
authors: Department of Chemistry and Biochemistry, University of Bern, Freiestr. 3, CH-3012 Bern, Switzerland.
authors: Silvia
authors: S
authors: Desy
authors: André
authors: A
authors: Schneider
authors: Jan
authors: J
authors: Mani
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D008666:Metalloendopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D011498:Protein Precursors / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014346:Trypanosoma brucei brucei / Q000201:enzymology* / Q000235:genetics; D000096122:Mitochondrial Processing Peptidase
chemical_list: D008666:Metalloendopeptidases; D024101:Mitochondrial Proteins; D011498:Protein Precursors; D021122:Protein Subunits; D000096122:Mitochondrial Processing Peptidase