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Gating of the voltage-dependent chloride channel CIC-0 by the permeant anion

Item Type:Article
Title:Gating of the voltage-dependent chloride channel CIC-0 by the permeant anion
Creators Name:Pusch, M. and Ludewig, U. and Rehfeldt, A. and Jentsch, T.J.
Abstract:Chloride channels of the ClC family are important for the control of membrane excitability, cell volume regulation, and possibly transepithelial transport. Although lacking the typical voltage-sensor found in cation channels, gating of ClC channels is clearly voltage-dependent. For the prototype Torpedo channel ClC-0 (refs 11-15) we now show that channel opening is strongly facilitated by external chloride. Other less permeable anions can substitute for chloride with less efficiency. ClC-0 conductance shows an anomalous mole fraction behaviour with Cl-/NO3- mixtures, suggesting a multi-ion pore. Gating shows a similar anomalous behaviour, tightly linking permeation to gating. Eliminating a positive charge at the cytoplasmic end of domain D12 changes kinetics, concentration dependence and halide selectivity of gating, and alters pore properties such as ion selectivity, single-channel conductance and rectification. Taken together, our results strongly suggest that in these channels voltage-dependent gating is conferred by the permeating ion itself, acting as the gating charge.
Keywords:Cultured Cells, Chloride Channels, Chlorides, Electrophysiology, Ion Channel Gating, Mutation, Oocytes, Recombinant Proteins, Torpedo, Animals, Xenopus
Source:Nature
ISSN:0028-0836
Publisher:Nature Publishing Group (U.K.)
Volume:373
Number:6514
Page Range:527-531
Date:9 February 1995
Official Publication:https://doi.org/10.1038/373527a0
PubMed:View item in PubMed

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