|
|
|
|
|
|
|
||
Original Article |
Correspondence to: Tsung-Yu Chen, Center for Neuroscience, University of California, 1544 Newton Court, Davis, California 95616. Fax:(530)757-8827 E-mail:tycchen{at}ucdavis.edu.
The fast gate of the muscle-type ClC channels (ClC-0 and ClC-1) opens in response to the change of membrane potential (V). This gating process is intimately associated with the binding of external Cl- to the channel pore in a way that the occupancy of Cl- on the binding site increases the channel's open probability (Po). External H+ also enhances the fast-gate opening in these channels, prompting a hypothesis that protonation of the binding site may increase the Cl- binding affinity, and this is possibly the underlying mechanism for the H+ modulation. However, Cl- and H+, modulate the fast-gate Po-V curve in different ways. Varying the external Cl- concentrations ([Cl-]o) shifts the Po-V curve in parallel along the voltage axis, whereas reducing external pH mainly increases the minimal Po of the curve. Furthermore, H+ modulations at saturating and nonsaturating [Cl-]o are similar. Thus, the H+ effect on the fast gating appears not to be a consequence of an increase in the Cl- binding affinity. We previously found that a hyperpolarization-favored opening process is important to determine the fast-gate Po of ClC-0 at very negative voltages. This [Cl-]o-independent mechanism attracted little attention, but it appears to be the opening process that is modulated by external H+.
Key Words: channel gating, ClC-0, ClC-1, pH regulation, Cl- dependence
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
 |
|
  J. Garcia-Olivares, A. Alekov, M. R. Boroumand, B. Begemann, P. Hidalgo, and C. Fahlke Gating of human ClC-2 chloride channels and regulation by carboxy-terminal domains J. Physiol., November 15, 2008; 586(22): 5325 - 5336. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. Zifarelli, A. R. Murgia, P. Soliani, and M. Pusch Intracellular Proton Regulation of ClC-0 J. Gen. Physiol., July 1, 2008; 132(1): 185 - 198. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. N. Thompson, D. J. Posson, P. V. Parsa, and C. M. Nimigean Molecular mechanism of pH sensing in KcsA potassium channels PNAS, May 13, 2008; 105(19): 6900 - 6905. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T.-Y. Chen and T.-C. Hwang CLC-0 and CFTR: Chloride Channels Evolved From Transporters Physiol Rev, April 1, 2008; 88(2): 351 - 387. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. J. Matsuda, M. S. Filali, K. A. Volk, M. M. Collins, J. G. Moreland, and F. S. Lamb Overexpression of CLC-3 in HEK293T cells yields novel currents that are pH dependent Am J Physiol Cell Physiol, January 1, 2008; 294(1): C251 - C262. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. M. Engh, J. D. Faraldo-Gomez, and M. Maduke The Mechanism of Fast-Gate Opening in ClC-0 J. Gen. Physiol., September 24, 2007; 130(4): 335 - 349. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X.-D. Zhang, Y. Li, W.-P. Yu, and T.-Y. Chen Roles of K149, G352, and H401 in the Channel Functions of ClC-0: Testing the Predictions from Theoretical Calculations J. Gen. Physiol., March 27, 2006; 127(4): 435 - 447. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Traverso, G. Zifarelli, R. Aiello, and M. Pusch Proton Sensing of CLC-0 Mutant E166D J. Gen. Physiol., December 27, 2005; 127(1): 51 - 66. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Accardi, M. Walden, W. Nguitragool, H. Jayaram, C. Williams, and C. Miller Separate Ion Pathways in a Cl-/H+ Exchanger J. Gen. Physiol., November 28, 2005; 126(6): 563 - 570. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. M. Czajkowsky, H. Iwamoto, G. Szabo, T. L. Cover, and Z. Shao Mimicry of a Host Anion Channel by a Helicobacter pylori Pore-Forming Toxin Biophys. J., November 1, 2005; 89(5): 3093 - 3101. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. D Duffield, G. Y Rychkov, A. H Bretag, and M. L Roberts Zinc inhibits human ClC-1 muscle chloride channel by interacting with its common gating mechanism J. Physiol., October 1, 2005; 568(1): 5 - 12. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Hebeisen and C. Fahlke Carboxy-Terminal Truncations Modify the Outer Pore Vestibule of Muscle Chloride Channels Biophys. J., September 1, 2005; 89(3): 1710 - 1720. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Bisset, B. Corry, and S.-H. Chung The Fast Gating Mechanism in ClC-0 Channels Biophys. J., July 1, 2005; 89(1): 179 - 186. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Li, W.-P. Yu, C.-W. Lin, and T.-Y. Chen Oxidation and Reduction Control of the Inactivation Gating of Torpedo ClC-0 Chloride Channels Biophys. J., June 1, 2005; 88(6): 3936 - 3945. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. M. Engh and M. Maduke Cysteine Accessibility in ClC-0 Supports Conservation of the ClC Intracellular Vestibule J. Gen. Physiol., May 31, 2005; 125(6): 601 - 617. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Nobles, C. F. Higgins, and A. Sardini Extracellular acidification elicits a chloride current that shares characteristics with ICl(swell) Am J Physiol Cell Physiol, November 1, 2004; 287(5): C1426 - C1435. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. Babini and M. Pusch A Two-Holed Story: Structural Secrets About ClC Proteins Become Unraveled? Physiology, October 1, 2004; 19(5): 293 - 299. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. L. Bostick and M. L. Berkowitz Exterior Site Occupancy Infers Chloride-Induced Proton Gating in a Prokaryotic Homolog of the ClC Chloride Channel Biophys. J., September 1, 2004; 87(3): 1686 - 1696. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Accardi, L. Kolmakova-Partensky, C. Williams, and C. Miller Ionic Currents Mediated by a Prokaryotic Homologue of CLC Cl- Channels J. Gen. Physiol., January 26, 2004; 123(2): 109 - 119. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T.-Y. Chen, M.-F. Chen, and C.-W. Lin Electrostatic Control and Chloride Regulation of the Fast Gating of ClC-0 Chloride Channels J. Gen. Physiol., October 27, 2003; 122(5): 641 - 651. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Accardi and M. Pusch Conformational Changes in the Pore of CLC-0 J. Gen. Physiol., August 25, 2003; 122(3): 277 - 294. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M.-F. Chen and T.-Y. Chen Side-chain Charge Effects and Conductance Determinants in the Pore of ClC-0 Chloride Channels J. Gen. Physiol., July 28, 2003; 122(2): 133 - 145. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C.-W. Lin and T.-Y. Chen Probing the Pore of ClC-0 by Substituted Cysteine Accessibility Method Using Methane Thiosulfonate Reagents J. Gen. Physiol., July 28, 2003; 122(2): 147 - 159. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T.-Y. Chen Coupling Gating with Ion Permeation in ClC Channels Sci. Signal., June 24, 2003; 2003(188): pe23 - pe23. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Dutzler, E. B. Campbell, and R. MacKinnon Gating the Selectivity Filter in ClC Chloride Channels Science, April 4, 2003; 300(5616): 108 - 112. [Abstract] [Full Text] [PDF]
|
|
|
|
