The control of mitochondrial respiration in yeast: a possible role of the outer mitochondrial membrane.
Mitochondrial respiration in yeast (S. cerevisiae) is regulated by the level of glucose in the medium. Glucose is known to inhibit respiration by repressing key enzymes in the respiratory chain. We present evidence that the early events in this inhibition include the closure of VDAC channels, the primary pathway for metabolite flow across the outer membrane. Aluminum hydroxide is known to inhibit the closure of VDAC. Addition of aluminum acetylacetonate to yeast cells, which should elevate the aluminum hydroxide concentrations in the cytoplasm, caused the inhibition of cell respiration by glucose to be delayed for up to 100 min. No significant effect of aluminum was observed in cells grown on glycerol. Yeast cells lacking the VDAC gene were also unresponsive to the addition of aluminum salt in the presence of glucose. Therefore, the closure of VDAC channels may be an early step in the inhibition of the respiration of yeast by glucose.
Ahmadzadeh
M
M
Department of Zoology, University of Maryland, College Park 20742, USA.
Horng
A
A
Colombini
M
M
D000536:Aluminum Hydroxide / Q000494:pharmacology; D005285:Fermentation; D005947:Glucose / Q000494:pharmacology*; D007425:Intracellular Membranes / Q000187:drug effects*; D007473:Ion Channels / Q000187:drug effects; D008565:Membrane Proteins / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects* / Q000648:ultrastructure; D010101:Oxygen Consumption / Q000187:drug effects*; D018272:Porins; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000648:ultrastructure; D050994:Voltage-Dependent Anion Channels
D007473:Ion Channels; D008565:Membrane Proteins; D018272:Porins; D050994:Voltage-Dependent Anion Channels; D000536:Aluminum Hydroxide; D005947:Glucose