Regulation of ClC-2 gating by intracellular ATP
| Autor: | Mohammad R. Toliat, Gabriel Stölting, Georgeta Teodorescu, Holger Lerche, Birgit Begemann, Peter Nürnberg, Julian Schubert, Christoph Fahlke, Thomas Sander, Rima Nabbout |
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| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Physiology
Clinical Biochemistry Intracellular Space Mutation Missense Gating chemistry.chemical_compound Protein structure Single-channel recording Adenosine Triphosphate Chloride Channels Physiology (medical) Humans Nucleotide ddc:610 Patch clamp Reversal potential chemistry.chemical_classification Epilepsy urogenital system Protein Structure Tertiary CLC-2 Chloride Channels HEK293 Cells Biochemistry chemistry Chloride channel Biophysics Epilepsy Generalized Channel gating Adenosine triphosphate Ion Channel Gating Intracellular Ion Channels Receptors and Transporters |
| Zdroj: | Pflugers Archiv Pflügers Archiv 465(10), 1423-1437 (2013). doi:10.1007/s00424-013-1286-0 |
| ISSN: | 1432-2013 0031-6768 |
| DOI: | 10.1007/s00424-013-1286-0 |
| Popis: | ClC-2 is a voltage-dependent chloride channel that activates slowly at voltages negative to the chloride reversal potential. Adenosine triphosphate (ATP) and other nucleotides have been shown to bind to carboxy-terminal cystathionine-ß-synthase (CBS) domains of ClC-2, but the functional consequences of binding are not sufficiently understood. We here studied the effect of nucleotides on channel gating using single-channel and whole-cell patch clamp recordings on transfected mammalian cells. ATP slowed down macroscopic activation and deactivation time courses in a dose-dependent manner. Removal of the complete carboxy-terminus abolishes the effect of ATP, suggesting that CBS domains are necessary for ATP regulation of ClC-2 gating. Single-channel recordings identified long-lasting closed states of ATP-bound channels as basis of this gating deceleration. ClC-2 channel dimers exhibit two largely independent protopores that are opened and closed individually as well as by a common gating process. A seven-state model of common gating with altered voltage dependencies of opening and closing transitions for ATP-bound states correctly describes the effects of ATP on macroscopic and microscopic ClC-2 currents. To test for a potential pathophysiological impact of ClC-2 regulation by ATP, we studied ClC-2 channels carrying naturally occurring sequence variants found in patients with idiopathic generalized epilepsy, G715E, R577Q, and R653T. All naturally occurring sequence variants accelerate common gating in the presence but not in the absence of ATP. We propose that ClC-2 uses ATP as a co-factor to slow down common gating for sufficient electrical stability of neurons under physiological conditions. Electronic supplementary material The online version of this article (doi:10.1007/s00424-013-1286-0) contains supplementary material, which is available to authorized users. |
| Databáze: | OpenAIRE |
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