Coupling gating with ion permeation in ClC channels.
In ClC chloride (Cl(-)) channels, unlike cation-selective ion channels, ion permeation is intimately coupled to fast gating. Recent research comparing the crystallographic structure of a bacterial ClC channel with functional studies of a Torpedo ClC channel suggests that gating depends on the negatively charged carboxyl group on a glutamate residue, which blocks the channel pore. In this model, the permeating Cl(-) competes with the carboxyl group for an anion-binding site in the channel pore. This model of Cl(-) competition with a glutamate gate helps explain the effect of intracellular Cl(-) on channel gating; the mechanism underlying the effects of extracellular Cl(-), however, remains to be determined, as does the nature of the Cl(-) channel slow gate.
Chen
Tsung-Yu
TY
Center for Neuroscience and Department of Neurology, University of California, Davis, CA 95616, USA. tycchen@ucdavis.edu
D000818:Animals; D002463:Cell Membrane Permeability / Q000502:physiology*; D018118:Chloride Channels / Q000378:metabolism / Q000502:physiology*; D002712:Chlorides / Q000378:metabolism*; D006801:Humans; D015640:Ion Channel Gating / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology; D018408:Patch-Clamp Techniques / Q000379:methods*
D018118:Chloride Channels; D002712:Chlorides