The mechanism for the ATP-induced uncoupling of respiration in mitochondria of the yeast Saccharomyces cerevisiae.
We have recently reported that ATP induces an uncoupling pathway in Saccharomyces cerevisiae mitochondria [Prieto, Bouillaud, Ricquier and Rial (1992) Eur. J. Biochem. 208, 487-491]. The presence of this pathway would explain the reported low efficiency of oxidative phosphorylation in S. cerevisiae, and may represent one of the postulated energy-dissipating mechanisms present in these yeasts. In this paper we demonstrate that ATP exerts its action in two steps: first, at low ATP/Pi ratios, it increases the respiratory-chain activity, probably by altering the kinetic properties of cytochrome c oxidase. Second, at higher ATP/Pi ratios, an increase in membrane permeability leads to a collapse in membrane potential. The ATP effect on cytochrome c oxidase corroborates a recent report showing that ATP interacts specifically with yeast cytochrome oxidase, stimulating its activity [Taanman and Capaldi (1993) J. Biol. Chem. 268, 18754-18761].
Prieto
S
S
Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain.
Bouillaud
F
F
Rial
E
E
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D003576:Electron Transport Complex IV / Q000187:drug effects / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007425:Intracellular Membranes / Q000187:drug effects / Q000502:physiology; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism*; D009243:NAD / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects*; D010539:Permeability / Q000187:drug effects; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000378:metabolism* / Q000648:ultrastructure
D009243:NAD; D000255:Adenosine Triphosphate; D003576:Electron Transport Complex IV