Ca2+ and nucleotide dependent regulation of voltage dependent anion channels in the plasma membrane of guard cells

EMBO J. 1990 Dec;9(12):3889-92.

Abstract

Using the patch-clamp technique we discovered that the voltage dependent anion channels in the plasma membrane of guard cells are activated by a rise in cytoplasmic Ca2+ in the presence of nucleotides. Upon activation, these anion channels catalyse anion currents 10-20 times higher than in the inactivated state, thus shifting the plasma membrane from a K+ conducting state to an anion conducting state. Prolonged stimulation by depolarizing voltages results in the inactivation of the anion current (t1/2 = 10-12 s). We suggest that activation of the anion channel by Ca2+ and nucleotides is a key event in the regulation of salt efflux from guard cells during stomatal closure.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / analogs & derivatives*
  • Adenosine Triphosphate / metabolism
  • Adenosine Triphosphate / pharmacology
  • Calcium / pharmacology*
  • Egtazic Acid / pharmacology
  • Fabaceae / physiology
  • Guanosine 5'-O-(3-Thiotriphosphate) / pharmacology*
  • Ion Channels / drug effects
  • Ion Channels / physiology*
  • Membrane Potentials / drug effects
  • Plant Cells
  • Plant Physiological Phenomena*
  • Plants, Medicinal
  • Potassium Channels / drug effects
  • Potassium Channels / physiology
  • Protoplasts / physiology

Substances

  • Ion Channels
  • Potassium Channels
  • adenosine 5'-O-(3-thiotriphosphate)
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • Egtazic Acid
  • Adenosine Triphosphate
  • Calcium