Mitochondria-associated yeast mRNAs and the biogenesis of molecular complexes

• Published in: Molecular biology of the cell Vol. 18; no. 2; pp. 362 - 368
• Main Authors: Garcia, M, Darzacq, X, Delaveau, T, Jourdren, L, Singer, R H, Jacq, C
• Format: Journal Article
• Language: English
• Published: United States American Society for Cell Biology 01.02.2007; The American Society for Cell Biology
• Subjects: Biochemistry, Molecular Biology; Carrier Proteins - genetics; Carrier Proteins - metabolism; In Situ Hybridization, Fluorescence; Life Sciences; Membrane Transport Proteins - genetics; Membrane Transport Proteins - metabolism; Mitochondria - chemistry; Mitochondria - metabolism; Mitochondrial Membranes - metabolism; Mitochondrial Proteins - genetics; Mitochondrial Proteins - metabolism; Protein Transport; RNA, Fungal - analysis; RNA, Fungal - metabolism; RNA, Messenger - analysis; RNA, Messenger - metabolism; Saccharomyces cerevisiae - chemistry; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism
• DOI: 10.1091/mbc.E06-09-0827
• ISSN: 1059-1524

The coherence of mitochondrial biogenesis relies on spatiotemporally coordinated associations of 800-1000 proteins mostly encoded in the nuclear genome. We report the development of new quantitative analyses to assess the role of local protein translation in the construction of molecular complexes. We used real-time PCR to determine the cellular location of 112 mRNAs involved in seven mitochondrial complexes. Five typical cases were examined by an improved FISH protocol. The proteins produced in the vicinity of mitochondria (MLR proteins) were, almost exclusively, of prokaryotic origin and are key elements of the core construction of the molecular complexes; the accessory proteins were translated on free cytoplasmic polysomes. These two classes of proteins correspond, at least as far as intermembrane space (IMS) proteins are concerned, to two different import pathways. Import of MLR proteins involves both TOM and TIM23 complexes whereas non-MLR proteins only interact with the TOM complex. Site-specific translation loci, both outside and inside mitochondria, may coordinate the construction of molecular complexes composed of both nuclearly and mitochondrially encoded subunits.