title: Ribosome recycling defects modify the balance between the synthesis and assembly of specific subunits of the oxidative phosphorylation complexes in yeast mitochondria.
abstract: Mitochondria have their own translation machinery that produces key subunits of the OXPHOS complexes. This machinery relies on the coordinated action of nuclear-encoded factors of bacterial origin that are well conserved between humans and yeast. In humans, mutations in these factors can cause diseases; in yeast, mutations abolishing mitochondrial translation destabilize the mitochondrial DNA. We show that when the mitochondrial genome contains no introns, the loss of the yeast factors Mif3 and Rrf1 involved in ribosome recycling neither blocks translation nor destabilizes mitochondrial DNA. Rather, the absence of these factors increases the synthesis of the mitochondrially-encoded subunits Cox1, Cytb and Atp9, while strongly impairing the assembly of OXPHOS complexes IV and V. We further show that in the absence of Rrf1, the COX1 specific translation activator Mss51 accumulates in low molecular weight forms, thought to be the source of the translationally-active form, explaining the increased synthesis of Cox1. We propose that Rrf1 takes part in the coordination between translation and OXPHOS assembly in yeast mitochondria. These interactions between general and specific translation factors might reveal an evolutionary adaptation of the bacterial translation machinery to the set of integral membrane proteins that are translated within mitochondria.
authors.affiliation: Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, UEVE, 91198, Gif-sur-Yvette cedex, France.
authors.forename: Jelena
authors.initials: J
authors.lastname: Ostojić
authors.affiliation: Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, UEVE, 91198, Gif-sur-Yvette cedex, France.
authors.forename: Cristina
authors.initials: C
authors.lastname: Panozzo
authors.affiliation: Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, UEVE, 91198, Gif-sur-Yvette cedex, France.
authors.forename: Alexa
authors.initials: A
authors.lastname: Bourand-Plantefol
authors.affiliation: Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, UEVE, 91198, Gif-sur-Yvette cedex, France.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Herbert
authors.affiliation: Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, UEVE, 91198, Gif-sur-Yvette cedex, France genevieve.dujardin@i2bc.paris-saclay.fr.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Dujardin
authors.affiliation: Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, UEVE, 91198, Gif-sur-Yvette cedex, France nathalie.bonnefoy@i2bc.paris-saclay.fr.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Bonnefoy
mesh_terms: D045303:Cytochromes b / Q000235:genetics / Q000378:metabolism; D004272:DNA, Mitochondrial / Q000235:genetics* / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D054629:Genome, Mitochondrial; D008928:Mitochondria / Q000235:genetics* / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D025261:Mitochondrial Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D010085:Oxidative Phosphorylation; D014176:Protein Biosynthesis; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D004272:DNA, Mitochondrial; D024101:Mitochondrial Proteins; C519191:Mss51 protein, S cerevisiae; C114727:RRF1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D045303:Cytochromes b; C526453:Cox1 protein, S cerevisiae; D003576:Electron Transport Complex IV; D025261:Mitochondrial Proton-Translocating ATPases; C491522:OLI1 protein, S cerevisiae