The control of mitochondrial respiration in yeast: A possible role of the outer mitochondrial membrane

Ahmadzadeh, Mojgan; Horng, Andrew; Colombini, Marco

doi:10.1002/cbf.673

Cited by 17 publications

(7 citation statements)

References 25 publications

(1 reference statement)

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“…The major source of ROS in most cell types is the mitochondrion, as by-products of aerobic respiration; therefore, we decided to investigate mitochondrial organization and function during starvation (Murphy, 2009). S. cerevisiae cells growing in glucose actively repress mitochondrial respiration and rely entirely on glycolysis for energy (Ahmadzadeh et al, 1996; Entian and Barnett, 1992). When the carbon source is changed to a nonfermentable one, such as glycerol, ethanol or acetate, cells switch to mitochondrial respiration as the major source of ATP (Boy-Marcotte et al, 1998).…”

Section: Resultsmentioning

confidence: 99%

Reactive oxygen species triggers unconventional secretion of antioxidants and Acb1

Cruz-García

Brouwers

Malhotra

et al. 2020

Journal of Cell Biology

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Nutrient deprivation triggers the release of signal-sequence–lacking Acb1 and the antioxidant superoxide dismutase 1 (SOD1). We now report that secreted SOD1 is functionally active and accompanied by export of other antioxidant enzymes such as thioredoxins (Trx1 and Trx2) and peroxiredoxin Ahp1 in a Grh1-dependent manner. Our data reveal that starvation leads to production of nontoxic levels of reactive oxygen species (ROS). Treatment of cells with N-acetylcysteine (NAC), which sequesters ROS, prevents antioxidants and Acb1 secretion. Starved cells lacking Grh1 are metabolically active, but defective in their ability to regrow upon return to growth conditions. Treatment with NAC restored the Grh1-dependent effect of starvation on cell growth. In sum, starvation triggers ROS production and cells respond by secreting antioxidants and the lipogenic signaling protein Acb1. We suggest that starvation-specific unconventional secretion of antioxidants and Acb1-like activities maintain cells in a form necessary for growth upon their eventual return to normal conditions.

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Section: Resultsmentioning

confidence: 99%

Reactive oxygen species triggers unconventional secretion of antioxidants and Acb1

Cruz-García

Brouwers

Malhotra

et al. 2020

Journal of Cell Biology

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“…2). Closure of VDAC channels, the primary pathway for metabolite flow across the outer membrane, has been shown to occur as an early step in the inhibition of respiration by glucose [45]. Since no change in the phosphorylation status of Por1p was observed after the diauxic shift, phosphorylation is probably not involved in VDAC opening or closure.…”

Section: Mitochondrial Outer Membranementioning

confidence: 94%

Protein phosphorylation in mitochondria – A study on fermentative and respiratory growth ofSaccharomyces cerevisiae

2010

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Phosphorylation as a posttranslational protein modification is a common subject of proteomic studies, but phosphorylation in mitochondria is still poorly investigated. The study presented here applied 2-DE to characterize phosphorylation in the yeast mitochondrial proteome and identified 59 spots corresponding to 34 phosphorylated mitochondrial or mitochondria-associated proteins. Most of these proteins presented putative substrates of mitogen-activated protein and target of rapamycin kinases, cAMP-dependent protein kinase, cyclin-dependent kinases and Snf1p suggesting them as key players in the phosphorylation of mitochondrial or mitochondria-associated proteins. The dynamic behaviour of the phosphoproteome under a major metabolic change, the shift from fermentation to respiration (diauxic shift), was further studied. Eight proteins (Ald4p, Eft1p/2p, Eno1p, Eno2p, Om14p, Pda1p, Qcr2p, Sdh1p) had growth dependent changes in their phosphorylation, indicating a role of phosphorylation-dependent regulation of translation, metabolic pathways (e.g. glucose fermentation, tricarboxylic acid cycle, pyruvate dehydrogenase and its bypass) and respiratory chain.

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“…These data agree with studies of porin import into mitochondria isolated from yeast coq5 mutant strains (14) demonstrating that the porin import is independent of Q 6 content or state of respiration. Some studies have indicated that porin is hyperexpressed in stationary phase, upon diauxic shift, and upon glucose deficiency (55,56). Other authors have indicated that the in vitro import of porin to mitochondria does not require ATP (57).…”

Section: Figmentioning

confidence: 99%

Uptake of Exogenous Coenzyme Q and Transport to Mitochondria Is Required for bc1 Complex Stability in Yeast coq Mutants

Santos-Ocaña¹,

Thai²,

Padilla³

et al. 2002

Journal of Biological Chemistry

101

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Coenzyme Q (Q) is an essential component of the mitochondrial respiratory chain in eukaryotic cells but also is present in other cellular membranes where it acts as an antioxidant. Because Q synthesis machinery in Saccharomyces cerevisiae is located in the mitochondria, the intracellular distribution of Q indicates the existence of intracellular Q transport. In this study, the uptake of exogenous Q 6 by yeast and its transport from the plasma membrane to mitochondria was assessed in both wild-type and in Q-less coq7 mutants derived from four distinct laboratory yeast strains. Q 6 supplementation of medium containing ethanol, a non-fermentable carbon source, rescued growth in only two of the four coq7 mutant strains. Following culture in medium containing dextrose, the added Q 6 was detected in the plasma membrane of each of four coq7 mutants tested. This detection of Q 6 in the plasma membrane was corroborated by measuring ascorbate stabilization activity, as catalyzed by NADH-ascorbate free radical reductase, a transmembrane redox activity that provides a functional assay of plasma membrane Q 6 . These assays indicate that each of the four coq7 mutant strains assimilate exogenous Q 6 into the plasma membrane. The two coq7 mutant strains rescued by Q 6 supplementation for growth on ethanol contained mitochondrial Q 6 levels similar to wild type. However, the content of Q 6 in mitochondria from the non-rescued strains was only 35 and 8%, respectively, of that present in the corresponding wild-type parental strains. In yeast strains rescued by exogenous Q 6 , succinate-cytochrome c reductase activity was partially restored, whereas non-rescued strains contained very low levels of activity. There was a strong correlation between mitochondrial Q 6 content, succinate-cytochrome c reductase activity, and steady state levels of the cytochrome c 1 polypeptide. These studies show that transport of extracellular Q 6 to the mitochondria operates in yeast but is strain-dependent. When Q biosynthesis is disrupted in yeast strains with defects in the intracellular transport of exogenous Q, the bc 1 complex is unstable. These results indicate that delivery of exogenous Q 6 to mitochondria is required fore activity and stability of the bc 1 complex in yeast coq mutants.

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The control of mitochondrial respiration in yeast: A possible role of the outer mitochondrial membrane

Cited by 17 publications

References 25 publications

Reactive oxygen species triggers unconventional secretion of antioxidants and Acb1

Reactive oxygen species triggers unconventional secretion of antioxidants and Acb1

Protein phosphorylation in mitochondria – A study on fermentative and respiratory growth ofSaccharomyces cerevisiae

Uptake of Exogenous Coenzyme Q and Transport to Mitochondria Is Required for bc1 Complex Stability in Yeast coq Mutants

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