H+ translocation by weak acid uncouplers is independent of H+ electrochemical gradient

J Bioenerg Biomembr. 2017 Oct;49(5):391-397. doi: 10.1007/s10863-017-9724-x. Epub 2017 Sep 12.

Abstract

According to the common view, weak acid uncouplers increase proton conductance of biological (and phospholipid bilayer) membranes, thus effecting H+ fluxes driven by their electrochemical gradients. Under certain conditions, however, uncouplers can induce unexpected effects opposite to the dissipation of H+ gradients. Results are presented here demonstrating CCCP-induced proton influx into Saccharomyces cerevisiae cytosol driven by the electrochemical potentials of CCCP and its CCCP- anions, independent of electrochemical H+-gradient. Another view of week acid uncouplers' action is proposed that is logically consistent with these observations.

Keywords: CCCP; Electrochemical H+ gradient; Mode of action; Saccharomyces cerevisiae; Weak acid uncouplers; pHluorin.

MeSH terms

  • Biological Transport / drug effects
  • Carbonyl Cyanide m-Chlorophenyl Hydrazone / pharmacology
  • Hydrogen-Ion Concentration / drug effects
  • Membrane Potentials* / drug effects
  • Protons*
  • Saccharomyces cerevisiae / metabolism*
  • Uncoupling Agents / pharmacology*

Substances

  • Protons
  • Uncoupling Agents
  • Carbonyl Cyanide m-Chlorophenyl Hydrazone