A genetic screen for dihydropyridine (DHP)-resistant worms reveals new residues required for DHP-blockage of mammalian calcium channels.
Dihydropyridines (DHPs) are L-type calcium channel (Ca(v)1) blockers prescribed to treat several diseases including hypertension. Ca(v)1 channels normally exist in three states: a resting closed state, an open state that is triggered by membrane depolarization, followed by a non-conducting inactivat...
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2008-05-01
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| Series: | PLoS Genetics |
| Online Access: | http://europepmc.org/articles/PMC2362100?pdf=render |
| _version_ | 1818943991984422912 |
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| author | Trevor C Y Kwok Kwokyin Hui Wojciech Kostelecki Nicole Ricker Guillermo Selman Zhong-Ping Feng Peter John Roy |
| author_facet | Trevor C Y Kwok Kwokyin Hui Wojciech Kostelecki Nicole Ricker Guillermo Selman Zhong-Ping Feng Peter John Roy |
| author_sort | Trevor C Y Kwok |
| collection | DOAJ |
| description | Dihydropyridines (DHPs) are L-type calcium channel (Ca(v)1) blockers prescribed to treat several diseases including hypertension. Ca(v)1 channels normally exist in three states: a resting closed state, an open state that is triggered by membrane depolarization, followed by a non-conducting inactivated state that is triggered by the influx of calcium ions, and a rapid change in voltage. DHP binding is thought to alter the conformation of the channel, possibly by engaging a mechanism similar to voltage dependent inactivation, and locking a calcium ion in the pore, thereby blocking channel conductance. As a Ca(v)1 channel crystal structure is lacking, the current model of DHP action has largely been achieved by investigating the role of candidate Ca(v)1 residues in mediating DHP-sensitivity. To better understand DHP-block and identify additional Ca(v)1 residues important for DHP-sensitivity, we screened 440,000 randomly mutated Caenorhabditis elegans genomes for worms resistant to DHP-induced growth defects. We identified 30 missense mutations in the worm Ca(v)1 pore-forming (alpha(1)) subunit, including eleven in conserved residues known to be necessary for DHP-binding. The remaining polymorphisms are in eight conserved residues not previously associated with DHP-sensitivity. Intriguingly, all of the worm mutants that we analyzed phenotypically exhibited increased channel activity. We also created orthologous mutations in the rat alpha(1C) subunit and examined the DHP-block of current through the mutant channels in culture. Six of the seven mutant channels examined either decreased the DHP-sensitivity of the channel and/or exhibited significant residual current at DHP concentrations sufficient to block wild-type channels. Our results further support the idea that DHP-block is intimately associated with voltage dependent inactivation and underscores the utility of C. elegans as a screening tool to identify residues important for DHP interaction with mammalian Ca(v)1 channels. |
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| issn | 1553-7390 1553-7404 |
| language | English |
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| publishDate | 2008-05-01 |
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| series | PLoS Genetics |
| spelling | doaj.art-5e963999ba1e40eea5763c15b2da353d2022-12-21T19:48:17ZengPublic Library of Science (PLoS)PLoS Genetics1553-73901553-74042008-05-0145e100006710.1371/journal.pgen.1000067A genetic screen for dihydropyridine (DHP)-resistant worms reveals new residues required for DHP-blockage of mammalian calcium channels.Trevor C Y KwokKwokyin HuiWojciech KosteleckiNicole RickerGuillermo SelmanZhong-Ping FengPeter John RoyDihydropyridines (DHPs) are L-type calcium channel (Ca(v)1) blockers prescribed to treat several diseases including hypertension. Ca(v)1 channels normally exist in three states: a resting closed state, an open state that is triggered by membrane depolarization, followed by a non-conducting inactivated state that is triggered by the influx of calcium ions, and a rapid change in voltage. DHP binding is thought to alter the conformation of the channel, possibly by engaging a mechanism similar to voltage dependent inactivation, and locking a calcium ion in the pore, thereby blocking channel conductance. As a Ca(v)1 channel crystal structure is lacking, the current model of DHP action has largely been achieved by investigating the role of candidate Ca(v)1 residues in mediating DHP-sensitivity. To better understand DHP-block and identify additional Ca(v)1 residues important for DHP-sensitivity, we screened 440,000 randomly mutated Caenorhabditis elegans genomes for worms resistant to DHP-induced growth defects. We identified 30 missense mutations in the worm Ca(v)1 pore-forming (alpha(1)) subunit, including eleven in conserved residues known to be necessary for DHP-binding. The remaining polymorphisms are in eight conserved residues not previously associated with DHP-sensitivity. Intriguingly, all of the worm mutants that we analyzed phenotypically exhibited increased channel activity. We also created orthologous mutations in the rat alpha(1C) subunit and examined the DHP-block of current through the mutant channels in culture. Six of the seven mutant channels examined either decreased the DHP-sensitivity of the channel and/or exhibited significant residual current at DHP concentrations sufficient to block wild-type channels. Our results further support the idea that DHP-block is intimately associated with voltage dependent inactivation and underscores the utility of C. elegans as a screening tool to identify residues important for DHP interaction with mammalian Ca(v)1 channels.http://europepmc.org/articles/PMC2362100?pdf=render |
| spellingShingle | Trevor C Y Kwok Kwokyin Hui Wojciech Kostelecki Nicole Ricker Guillermo Selman Zhong-Ping Feng Peter John Roy A genetic screen for dihydropyridine (DHP)-resistant worms reveals new residues required for DHP-blockage of mammalian calcium channels. PLoS Genetics |
| title | A genetic screen for dihydropyridine (DHP)-resistant worms reveals new residues required for DHP-blockage of mammalian calcium channels. |
| title_full | A genetic screen for dihydropyridine (DHP)-resistant worms reveals new residues required for DHP-blockage of mammalian calcium channels. |
| title_fullStr | A genetic screen for dihydropyridine (DHP)-resistant worms reveals new residues required for DHP-blockage of mammalian calcium channels. |
| title_full_unstemmed | A genetic screen for dihydropyridine (DHP)-resistant worms reveals new residues required for DHP-blockage of mammalian calcium channels. |
| title_short | A genetic screen for dihydropyridine (DHP)-resistant worms reveals new residues required for DHP-blockage of mammalian calcium channels. |
| title_sort | genetic screen for dihydropyridine dhp resistant worms reveals new residues required for dhp blockage of mammalian calcium channels |
| url | http://europepmc.org/articles/PMC2362100?pdf=render |
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