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Catalyst-like modulation of transition states for CFTR channel opening and closing: New stimulation strategy exploits nonequilibrium gating

Cystic fibrosis transmembrane conductance regulator (CFTR) is the chloride ion channel mutated in cystic fibrosis (CF) patients. It is an ATP-binding cassette protein, and its resulting cyclic nonequilibrium gating mechanism sets it apart from most other ion channels. The most common CF mutation (ΔF...

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Autores principales: Csanády, László, Töröcsik, Beáta
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Rockefeller University Press 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4001772/
https://www.ncbi.nlm.nih.gov/pubmed/24420771
http://dx.doi.org/10.1085/jgp.201311089
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author Csanády, László
Töröcsik, Beáta
author_facet Csanády, László
Töröcsik, Beáta
author_sort Csanády, László
collection PubMed
description Cystic fibrosis transmembrane conductance regulator (CFTR) is the chloride ion channel mutated in cystic fibrosis (CF) patients. It is an ATP-binding cassette protein, and its resulting cyclic nonequilibrium gating mechanism sets it apart from most other ion channels. The most common CF mutation (ΔF508) impairs folding of CFTR but also channel gating, reducing open probability (P(o)). This gating defect must be addressed to effectively treat CF. Combining single-channel and macroscopic current measurements in inside-out patches, we show here that the two effects of 5-nitro-2-(3-phenylpropylamino)benzoate (NPPB) on CFTR, pore block and gating stimulation, are independent, suggesting action at distinct sites. Furthermore, detailed kinetic analysis revealed that NPPB potently increases P(o), also of ΔF508 CFTR, by affecting the stability of gating transition states. This finding is unexpected, because for most ion channels, which gate at equilibrium, altering transition-state stabilities has no effect on P(o); rather, agonists usually stimulate by stabilizing open states. Our results highlight how for CFTR, because of its unique cyclic mechanism, gating transition states determine P(o) and offer strategic targets for potentiator compounds to achieve maximal efficacy.
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spelling pubmed-40017722014-08-01 Catalyst-like modulation of transition states for CFTR channel opening and closing: New stimulation strategy exploits nonequilibrium gating Csanády, László Töröcsik, Beáta J Gen Physiol Research Articles Cystic fibrosis transmembrane conductance regulator (CFTR) is the chloride ion channel mutated in cystic fibrosis (CF) patients. It is an ATP-binding cassette protein, and its resulting cyclic nonequilibrium gating mechanism sets it apart from most other ion channels. The most common CF mutation (ΔF508) impairs folding of CFTR but also channel gating, reducing open probability (P(o)). This gating defect must be addressed to effectively treat CF. Combining single-channel and macroscopic current measurements in inside-out patches, we show here that the two effects of 5-nitro-2-(3-phenylpropylamino)benzoate (NPPB) on CFTR, pore block and gating stimulation, are independent, suggesting action at distinct sites. Furthermore, detailed kinetic analysis revealed that NPPB potently increases P(o), also of ΔF508 CFTR, by affecting the stability of gating transition states. This finding is unexpected, because for most ion channels, which gate at equilibrium, altering transition-state stabilities has no effect on P(o); rather, agonists usually stimulate by stabilizing open states. Our results highlight how for CFTR, because of its unique cyclic mechanism, gating transition states determine P(o) and offer strategic targets for potentiator compounds to achieve maximal efficacy. The Rockefeller University Press 2014-02 /pmc/articles/PMC4001772/ /pubmed/24420771 http://dx.doi.org/10.1085/jgp.201311089 Text en © 2014 Csanády and Töröcsik This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/).
spellingShingle Research Articles
Csanády, László
Töröcsik, Beáta
Catalyst-like modulation of transition states for CFTR channel opening and closing: New stimulation strategy exploits nonequilibrium gating
title Catalyst-like modulation of transition states for CFTR channel opening and closing: New stimulation strategy exploits nonequilibrium gating
title_full Catalyst-like modulation of transition states for CFTR channel opening and closing: New stimulation strategy exploits nonequilibrium gating
title_fullStr Catalyst-like modulation of transition states for CFTR channel opening and closing: New stimulation strategy exploits nonequilibrium gating
title_full_unstemmed Catalyst-like modulation of transition states for CFTR channel opening and closing: New stimulation strategy exploits nonequilibrium gating
title_short Catalyst-like modulation of transition states for CFTR channel opening and closing: New stimulation strategy exploits nonequilibrium gating
title_sort catalyst-like modulation of transition states for cftr channel opening and closing: new stimulation strategy exploits nonequilibrium gating
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4001772/
https://www.ncbi.nlm.nih.gov/pubmed/24420771
http://dx.doi.org/10.1085/jgp.201311089
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