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

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Item Type:	Article
Title:	Gating of the voltage-dependent chloride channel CIC-0 by the permeant anion
Creators Name:	Pusch, M., Ludewig, U., 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
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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