Investigation of the yeast mitochondrial unselective channel in intact and permeabilized spheroplasts.
The existence of an activity corresponding to the nucleotide-induced Yeast Mitochondria Unselective Channel (YMUC2) of isolated mitochondria was investigated in permeabilized and intact spheroplasts of the baker's yeast Yeast Foam. In nystatin-permeabilized spheroplasts, ATP and GDP-beta-S induced a decavanadate-sensitive stimulation of the respiration only under conditions equivalent to those previously reported for isolated mitochondria (low phosphate concentration, presence of a salt). On intact spheroplasts parallel measurements of respiration rate, [ATP]/[ADP] ratio and mitochondrial transmembrane potential allowed to show that the addition of the glucose analog 2-deoxyglucose decreased the permeability of the inner mitochondrial membrane owing to cellular ATP depletion. This strongly supports the hypothesis that Yeast Mitochondria Unspecific Channel is active in situ and inhibited by cellular [ATP] depletion.
Manon
S
S
Institut de Biochimie et de Génétique Cellulaires du Centre National de la Recherche Scientifique, Université Victor Ségalen-Bordeaux II, France. stephen.manon@ibgc.u-bordeaux2.fr
Guérin
M
M
D000244:Adenosine Diphosphate / Q000378:metabolism / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002463:Cell Membrane Permeability / Q000187:drug effects; D019069:Cell Respiration / Q000187:drug effects; D003847:Deoxyglucose / Q000494:pharmacology; D007473:Ion Channels / Q000378:metabolism*; D019344:Lactic Acid / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D009243:NAD / Q000378:metabolism / Q000494:pharmacology; D009761:Nystatin / Q000494:pharmacology; D010710:Phosphates / Q000378:metabolism / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D013012:Sorbitol / Q000494:pharmacology; D013104:Spheroplasts / Q000737:chemistry / Q000378:metabolism*; D014267:Triethyltin Compounds / Q000494:pharmacology
D007473:Ion Channels; D010710:Phosphates; D014267:Triethyltin Compounds; D009243:NAD; D009761:Nystatin; D019344:Lactic Acid; D013012:Sorbitol; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; C031575:triethyltin; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D003847:Deoxyglucose