Regulation of potassium fluxes in Saccharomyces cerevisiae

Biochim Biophys Acta. 1990 Nov 16;1029(2):211-7. doi: 10.1016/0005-2736(90)90156-i.

Abstract

To investigate the regulation of K+ fluxes in Saccharomyces cerevisiae the dependence of K+ efflux and Rb+ influx on [K+]i, pHi, [Na+]i, membrane potential, cell volume, and turgor pressure were studied in cells with different K+ contents. By decreasing the cell volume with osmotic shocks and the cellular pH with butyric acid the following was found. (1) The K+ efflux induced by uncouplers decreases simultaneously with the decrease of the K+ content of the cell, but the process was insensitive to [K+]i, pHi, cell volume and turgor pressure. The internal presence of Na+ inhibited this K+ efflux. (2) The increase of the Vmax of Rb+ influx observed in low-K+ cells is due to the decrease of the pHi and probably mediated by the increase of the activity of the plasma membrane ATPase. The Vmax is independent of [K+]i, [Na+]i, cell volume and turgor pressure. (3) The decrease in the Km of Bt+ influx observed in low-K+ cells does not depend directly on [K+]i, pHi, cell volume or turgor pressure. If Na+ is present, [Na+]i might be directly involved in the regulation of the Km.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbonyl Cyanide m-Chlorophenyl Hydrazone / pharmacology
  • Hydrogen-Ion Concentration
  • Mutation
  • Potassium / metabolism*
  • Rubidium / pharmacokinetics
  • Saccharomyces cerevisiae / metabolism*

Substances

  • Carbonyl Cyanide m-Chlorophenyl Hydrazone
  • Rubidium
  • Potassium