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

Pusch, M. and Ludewig, Uwe and Rehfeldt, A. and Jentsch, T. J. :
Gating of the voltage-dependent chloride channel CIC-0 by the permeant anion.
In: Nature, 373 (6514) pp. 527-31. ISSN 0028-0836
[Article] , (1995)

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.

Item Type: Article
Erschienen: 1995
Creators: Pusch, M. and Ludewig, Uwe and Rehfeldt, A. and Jentsch, T. J.
Title: Gating of the voltage-dependent chloride channel CIC-0 by the permeant anion.
Language: English
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.

Journal or Publication Title: Nature
Volume: 373
Number: 6514
Divisions: 10 Department of Biology > Plant Nutrition and Biomass
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10 Department of Biology
Date Deposited: 16 Mar 2010 15:11
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