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Regulation of mitochondrial metabolism under respiratory and fermentative conditions in yeast Michel Rigoulet.

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Presentation on theme: "Regulation of mitochondrial metabolism under respiratory and fermentative conditions in yeast Michel Rigoulet."— Presentation transcript:

1 Regulation of mitochondrial metabolism under respiratory and fermentative conditions in yeast Michel Rigoulet

2 I Crabtree Effect Repression of respiration by glucose Short term and long term events Crabtree positive and Crabtree negative strains

3 Yeast growth on 0.6% glucose

4 The main glucose-repression pathway

5 Diauxic shift

6 Diauxic shift: Induction of glyoxylate pathway dehydrogenases and Krebs cycle enzymes oxidative phosphorylation gluconeogenesis

7 In Out I : Internal NADH dehydrogenase (Ndip) Ii : Succinate dehydrogenase III : External NADH dehydrogenase (Nde1p ; Nde2p) IV : Glycerol-3-P dehydrogenase (Gut2p) V : Lactate dehydrogenase VI : Glycerol-3-P dehydrogenase (Gpd1p ; Gpd2p) Dehydrogenases and respiratory chain in Saccharomyces cerevisiae

8 Measurement of Respiratory Control

9 Short term effect of glucose addition to respiring yeast: inhibition of respiration as a consequence of ?? Hypothesis 1) competition for free ADP and Pi 2) increase in phosphate potential (∆Gp) 3) activation of pyruvate decarboxylase 4) decrease in the outer membrane permeability for ADP (VDAC closed) new hypothesis: role of hexose-phosphate

10 Glycolysis Lipid biogenesis mitochondria

11 Non-phosphorylating conditionsPhosphorylating conditions  G6P ;   F6P ;  F1,6bP Effect of glycolysis-derived hexoses-phosphate on the respiratory flux of isolated mitochondria in Crabtree-positive yeast

12 Effect of F1,6bP on the G6P induced increase in the respiratory flux

13 In Out I : Internal NADH dehydrogenase (Ndip) Ii : Succinate dehydrogenase III : External NADH dehydrogenase (Nde1p ; Nde2p) IV : Glycerol-3-P dehydrogenase (Gut2p) V : Lactate dehydrogenase VI : Glycerol-3-P dehydrogenase (Gpd1p ; Gpd2p) Dehydrogenases and respiratory chain in Saccharomyces cerevisiae

14  Non-phosphorylating conditions ;  Phosphorylating conditions Cytochrome oxydase activity in the presence of F1,6bP

15  G6P ;   F6P ;  F1,6bP Effect of glycolysis-derived hexoses-phosphate on the mitochondrial complex III

16 Effect of F1,6bP on the G6P induced stimulation of complex III activity

17 Effect of glycolysis-derived hexoses-phosphate on the respiratory flux of isolated mitochondria in Crabtree-negative yeast

18 Phosphorylating conditions Effect of F1,6bP on the respiratory flux in rat liver mitochondria


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