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On the mechanism of CFTR inhibition by a thiazolidinone derivative
The effects of a thiazolidinone derivative, 3-[(3-trifluoromethyl)phenyl]-5-[(4-carboxyphenyl)methylene]-2-thioxo-4-thiazolidinone (or CFTRinh-172), on cystic fibrosis transmembrane conductance regulator (CFTR) gating were studied in excised inside-out membrane patches from Chinese hamster ovary cel...
Autores principales: | , , , |
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Formato: | Texto |
Lenguaje: | English |
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The Rockefeller University Press
2010
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2995156/ https://www.ncbi.nlm.nih.gov/pubmed/21078867 http://dx.doi.org/10.1085/jgp.201010518 |
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author | Kopeikin, Zoia Sohma, Yoshiro Li, Min Hwang, Tzyh-Chang |
author_facet | Kopeikin, Zoia Sohma, Yoshiro Li, Min Hwang, Tzyh-Chang |
author_sort | Kopeikin, Zoia |
collection | PubMed |
description | The effects of a thiazolidinone derivative, 3-[(3-trifluoromethyl)phenyl]-5-[(4-carboxyphenyl)methylene]-2-thioxo-4-thiazolidinone (or CFTRinh-172), on cystic fibrosis transmembrane conductance regulator (CFTR) gating were studied in excised inside-out membrane patches from Chinese hamster ovary cells transiently expressing wild-type and mutant CFTR. We found that the application of CFTRinh-172 results in an increase of the mean closed time and a decrease of the mean open time of the channel. A hyperbolic relationship between the closing rate and [CFTRinh-172] suggests that CFTRinh-172 does not act as a simple pore blocker. Interestingly, the potency of inhibition increases as the open time of the channel is increased with an IC50 in the low nanomolar range for CFTR channels locked in an open state for tens of seconds. Our studies also provide evidence that CFTRinh-172 can bind to both the open state and the closed state. However, at least one additional step, presumably reflecting inhibitor-induced conformational changes, is required to shut down the conductance after the binding of the inhibitor to the channel. Using the hydrolysis-deficient mutant E1371S as a tool as the closing rate of this mutant is dramatically decreased, we found that CFTRinh-172–dependent inhibition of CFTR channel gating, in two aspects, mimics the inactivation of voltage-dependent cation channels. First, similar to the recovery from inactivation in voltage-gated channels, once CFTR is inhibited by CFTRinh-172, reopening of the channel can be seen upon removal of the inhibitor in the absence of adenosine triphosphate (ATP). Second, ATP induced a biphasic current response on inhibitor-bound closed channels as if the ATP-opened channels “inactivate” despite a continuous presence of ATP. A simplified six-state kinetic scheme can well describe our data, at least qualitatively. Several possible structural mechanisms for the effects of CFTRinh-172 will be discussed. |
format | Text |
id | pubmed-2995156 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2010 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-29951562011-06-01 On the mechanism of CFTR inhibition by a thiazolidinone derivative Kopeikin, Zoia Sohma, Yoshiro Li, Min Hwang, Tzyh-Chang J Gen Physiol Article The effects of a thiazolidinone derivative, 3-[(3-trifluoromethyl)phenyl]-5-[(4-carboxyphenyl)methylene]-2-thioxo-4-thiazolidinone (or CFTRinh-172), on cystic fibrosis transmembrane conductance regulator (CFTR) gating were studied in excised inside-out membrane patches from Chinese hamster ovary cells transiently expressing wild-type and mutant CFTR. We found that the application of CFTRinh-172 results in an increase of the mean closed time and a decrease of the mean open time of the channel. A hyperbolic relationship between the closing rate and [CFTRinh-172] suggests that CFTRinh-172 does not act as a simple pore blocker. Interestingly, the potency of inhibition increases as the open time of the channel is increased with an IC50 in the low nanomolar range for CFTR channels locked in an open state for tens of seconds. Our studies also provide evidence that CFTRinh-172 can bind to both the open state and the closed state. However, at least one additional step, presumably reflecting inhibitor-induced conformational changes, is required to shut down the conductance after the binding of the inhibitor to the channel. Using the hydrolysis-deficient mutant E1371S as a tool as the closing rate of this mutant is dramatically decreased, we found that CFTRinh-172–dependent inhibition of CFTR channel gating, in two aspects, mimics the inactivation of voltage-dependent cation channels. First, similar to the recovery from inactivation in voltage-gated channels, once CFTR is inhibited by CFTRinh-172, reopening of the channel can be seen upon removal of the inhibitor in the absence of adenosine triphosphate (ATP). Second, ATP induced a biphasic current response on inhibitor-bound closed channels as if the ATP-opened channels “inactivate” despite a continuous presence of ATP. A simplified six-state kinetic scheme can well describe our data, at least qualitatively. Several possible structural mechanisms for the effects of CFTRinh-172 will be discussed. The Rockefeller University Press 2010-12 /pmc/articles/PMC2995156/ /pubmed/21078867 http://dx.doi.org/10.1085/jgp.201010518 Text en © 2010 Kopeikin et al. 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 | Article Kopeikin, Zoia Sohma, Yoshiro Li, Min Hwang, Tzyh-Chang On the mechanism of CFTR inhibition by a thiazolidinone derivative |
title | On the mechanism of CFTR inhibition by a thiazolidinone derivative |
title_full | On the mechanism of CFTR inhibition by a thiazolidinone derivative |
title_fullStr | On the mechanism of CFTR inhibition by a thiazolidinone derivative |
title_full_unstemmed | On the mechanism of CFTR inhibition by a thiazolidinone derivative |
title_short | On the mechanism of CFTR inhibition by a thiazolidinone derivative |
title_sort | on the mechanism of cftr inhibition by a thiazolidinone derivative |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2995156/ https://www.ncbi.nlm.nih.gov/pubmed/21078867 http://dx.doi.org/10.1085/jgp.201010518 |
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