ATP-induced unspecific channel in yeast mitochondria

J Biol Chem. 1994 Oct 14;269(41):25406-10.

Abstract

ATP induced swelling of isolated yeast mitochondria suspended in an isoosmotic solution of potassium gluconate. Valinomycin stimulated the swelling rate, indicating that K+ influx in the presence of ATP is rate-controlling. This swelling was inhibited by ADP, phosphate (probably acting on the external face of the inner membrane), and Mg2+, which forms a complex with ATP. ATP-induced swelling did not require working F0-F1-ATPase since it was not inhibited by oligomycin and uncoupler. CTP and GTP also induced a swelling. ATP also induced mitochondrial swelling in potassium glutamate, chloride, and acetate but not in phosphate solutions. Sodium, but not ammonium, can replace potassium ion. It is probable that the ATP-channel opening also necessitates an electrogenic cation influx. Respiration also induced swelling of mitochondria suspended in isoosmotic potassium gluconate solution. ATP- or respiration-induced swelling were inhibited equally by N,N'-dicyclohexylcarbodiimide, propranolol, and Zn2+ but not by quinine; all these drugs inhibit the H+/K+ exchange. It was concluded that this unspecific channel is not open under conditions used to measure oxidative phosphorylation. Its physiological role remains unknown.

Publication types

  • Comparative Study

MeSH terms

  • Acetates / pharmacology
  • Adenosine Diphosphate / pharmacology
  • Adenosine Triphosphate / pharmacology*
  • Biological Transport
  • Dose-Response Relationship, Drug
  • Gluconates / pharmacology
  • Hydrogen-Ion Concentration
  • Ion Channels / drug effects
  • Ion Channels / metabolism*
  • Magnesium / pharmacology
  • Mitochondria / metabolism*
  • Oxidative Phosphorylation
  • Particle Size
  • Phosphates / pharmacology
  • Potassium / pharmacology
  • Quinine / pharmacology
  • Saccharomyces cerevisiae / metabolism*

Substances

  • Acetates
  • Gluconates
  • Ion Channels
  • Phosphates
  • Adenosine Diphosphate
  • Adenosine Triphosphate
  • Quinine
  • Magnesium
  • Potassium