Membrane cholesterol content modulates ClC-2 gating and sensitivity to oxidative stress

J Biol Chem. 2007 Jan 26;282(4):2423-32. doi: 10.1074/jbc.M608251200. Epub 2006 Nov 15.

Abstract

ClC-2 is a broadly expressed member of the voltage-gated ClC chloride channel family. In this study, we aimed to evaluate the role of the membrane lipid environment in ClC-2 function, and in particular the effect of cholesterol and ClC-2 distribution in membrane microdomains. Detergent-resistant and detergent-soluble microdomains (DSM) were isolated from stably transfected HEK293 cells by a discontinuous OptiPrep gradient. ClC-2 was found concentrated in detergent-insoluble membranes in basal conditions and relocalized to DSM upon cholesterol depletion by methyl-beta-cyclodextrin. As assessed by patch clamp recordings, relocalization was accompanied by acceleration of the activation kinetics of the channel. A similar distribution and activation pattern were obtained when cells were treated with the oxidant tert-butyl hydroperoxide and after ATP depletion. In both cases activation was prevented by cholesterol enrichment of cells. We conclude that the cholesterol environment regulates ClC-2 activity, and we provide evidence that the increase in ClC-2 activity in response to acute oxidative or metabolic stress involves relocalization of this channel to DSM.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biological Transport
  • Cell Line
  • Chloride Channels / metabolism*
  • Cholesterol / metabolism
  • Humans
  • Ion Channel Gating*
  • Membrane Lipids / metabolism*
  • Membrane Microdomains / metabolism
  • Membrane Potentials
  • Oxidative Stress
  • Patch-Clamp Techniques
  • Rats

Substances

  • Chloride Channels
  • Membrane Lipids
  • Cholesterol