Project description:Reduction of mitochondrial membrane potential is a hallmark of mitochondrial dysfunction. It activates adaptive responses in organisms from yeast to human to rewire metabolism, remove depolarized mitochondria, and degrade unimported precursor proteins. It remains unclear how cells maintain mitochondrial membrane potential, which is critical for maintaining iron-sulfur cluster (ISC) synthesis, an indispensable function of mitochondria. Here we show that yeast oxidative phosphorylation mutants deficient in complex III, IV, V, and mtDNA respectively, have graded reduction of mitochondrial membrane potential and proliferation rates. Extensive omics analyses of these mutants show that accompanying mitochondrial membrane potential reduction, these mutants progressively activate adaptive responses, including transcriptional downregulation of ATP synthase inhibitor Inh1 and OXPHOS subunits, Puf3-mediated upregulation of import receptor Mia40 and global mitochondrial biogenesis, Snf1/AMPK-mediated upregulation of glycolysis and repression of ribosome biogenesis, and transcriptional upregulation of cytoplasmic chaperones. These adaptations disinhibit mitochondrial ATP hydrolysis, remodel mitochondrial proteome, and optimize ATP supply to mitochondria to convergently maintain mitochondrial membrane potential, ISC biosynthesis, and cell proliferation.
Project description:We investigated the transcriptional response of yeast to the loss of a single copy of ARH1; an oxidoreductase of the mitochondrial inner membrane, which is among the few mitochondrial proteins that is essential for viability in yeast, ATM1; the mitochondrial inner membrane ATP-binding cassette (ABC) transporter, and of YFH1; the mitochondrial matrix iron chaperone, which oxidizes and stores iron, and interacts with Isu1p to promote Fe-S cluster assembly.
Project description:Transcriptome comparisons between grx5, pet117 and mlp1 mutants. All of them are referenced to the same parental wild type sample using three independent samples and three independent nylon macroarrays. Each replicate pair (wt/mutant), hybridized on the same membrane, was normalized by lowess method. z-tests were performed to evaluate differential gene expression. Keywords = yeast Keywords = GRX5 Keywords = PET117 Keywords: other
Project description:Transcriptional profiles on different yeast strain mutants (DEgd2/1, DEgd2/Btt1)were identified by microarray analysis comparing total mutant RNA vs wild type RNA.
Project description:Yeast cells were stained with TMRE, which measures mitochondrial membrane potential, and were sorted onto four bins - HI,M1,M2 and LO, from TMRE vs cell-size plot. Total RNA was isolated from cells and RNA sequencing was done to compare transcriptome profile in sub-population of cells that differ in mitochondrial membrane potential. Cells with high potential showed repression of respiration genes, exhibited signs of DNA damage and iron deficiency.
