title: Proteomic profiling of the mitochondrial ribosome identifies Atp25 as a composite mitochondrial precursor protein.
abstract: Whereas the structure and function of cytosolic ribosomes are well characterized, we only have a limited understanding of the mitochondrial translation apparatus. Using SILAC-based proteomic profiling, we identified 13 proteins that cofractionated with the mitochondrial ribosome, most of which play a role in translation or ribosomal biogenesis. One of these proteins is a homologue of the bacterial ribosome-silencing factor (Rsf). This protein is generated from the composite precursor protein Atp25 upon internal cleavage by the matrix processing peptidase MPP, and in this respect, it differs from all other characterized mitochondrial proteins of baker's yeast. We observed that cytosolic expression of Rsf, but not of noncleaved Atp25 protein, is toxic. Our results suggest that eukaryotic cells face the challenge of avoiding negative interference from the biogenesis of their two distinct translation machineries.
authors: Cell Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany.
authors: Michael W
authors: MW
authors: Woellhaf
authors: Molecular Biotechnology and Systems Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany.
authors: Frederik
authors: F
authors: Sommer
authors: Molecular Biotechnology and Systems Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany.
authors: Michael
authors: M
authors: Schroda
authors: Cell Biology, University of Kaiserslautern, 67663 Kaiserslautern, Germany hannes.herrmann@biologie.uni-kl.de.
authors: Johannes M
authors: JM
authors: Herrmann
mesh_terms: D000595:Amino Acid Sequence; D020869:Gene Expression Profiling / Q000379:methods; D008666:Metalloendopeptidases / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins; D000069396:Mitochondrial Ribosomes / Q000378:metabolism* / Q000502:physiology; D014176:Protein Biosynthesis / Q000502:physiology; D011498:Protein Precursors / Q000378:metabolism; D040901:Proteomics / Q000379:methods; D012269:Ribosomal Proteins / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D000096122:Mitochondrial Processing Peptidase
chemical_list: D008666:Metalloendopeptidases; D024101:Mitochondrial Proteins; D011498:Protein Precursors; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D000096122:Mitochondrial Processing Peptidase; C483943:Rsf1 protein, S cerevisiae