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An epilepsy-causing mutation leads to co-translational misfolding of the Kv7.2 channel

BACKGROUND: The amino acid sequence of proteins generally carries all the necessary information for acquisition of native conformations, but the vectorial nature of translation can additionally determine the folding outcome. Such consideration is particularly relevant in human diseases associated to...

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Autores principales: Urrutia, Janire, Aguado, Alejandra, Gomis-Perez, Carolina, Muguruza-Montero, Arantza, Ballesteros, Oscar R., Zhang, Jiaren, Nuñez, Eider, Malo, Covadonga, Chung, Hee Jung, Leonardo, Aritz, Bergara, Aitor, Villarroel, Alvaro
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8138981/
https://www.ncbi.nlm.nih.gov/pubmed/34020651
http://dx.doi.org/10.1186/s12915-021-01040-1
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author Urrutia, Janire
Aguado, Alejandra
Gomis-Perez, Carolina
Muguruza-Montero, Arantza
Ballesteros, Oscar R.
Zhang, Jiaren
Nuñez, Eider
Malo, Covadonga
Chung, Hee Jung
Leonardo, Aritz
Bergara, Aitor
Villarroel, Alvaro
author_facet Urrutia, Janire
Aguado, Alejandra
Gomis-Perez, Carolina
Muguruza-Montero, Arantza
Ballesteros, Oscar R.
Zhang, Jiaren
Nuñez, Eider
Malo, Covadonga
Chung, Hee Jung
Leonardo, Aritz
Bergara, Aitor
Villarroel, Alvaro
author_sort Urrutia, Janire
collection PubMed
description BACKGROUND: The amino acid sequence of proteins generally carries all the necessary information for acquisition of native conformations, but the vectorial nature of translation can additionally determine the folding outcome. Such consideration is particularly relevant in human diseases associated to inherited mutations leading to structural instability, aggregation, and degradation. Mutations in the KCNQ2 gene associated with human epilepsy have been suggested to cause misfolding of the encoded Kv7.2 channel. Although the effect on folding of mutations in some domains has been studied, little is known of the way pathogenic variants located in the calcium responsive domain (CRD) affect folding. Here, we explore how a Kv7.2 mutation (W344R) located in helix A of the CRD and associated with hereditary epilepsy interferes with channel function. RESULTS: We report that the epilepsy W344R mutation within the IQ motif of CRD decreases channel function, but contrary to other mutations at this site, it does not impair the interaction with Calmodulin (CaM) in vitro, as monitored by multiple in vitro binding assays. We find negligible impact of the mutation on the structure of the complex by molecular dynamic computations. In silico studies revealed two orientations of the side chain, which are differentially populated by WT and W344R variants. Binding to CaM is impaired when the mutated protein is produced in cellulo but not in vitro, suggesting that this mutation impedes proper folding during translation within the cell by forcing the nascent chain to follow a folding route that leads to a non-native configuration, and thereby generating non-functional ion channels that fail to traffic to proper neuronal compartments. CONCLUSIONS: Our data suggest that the key pathogenic mechanism of Kv7.2 W344R mutation involves the failure to adopt a configuration that can be recognized by CaM in vivo but not in vitro. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12915-021-01040-1.
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spelling pubmed-81389812021-05-21 An epilepsy-causing mutation leads to co-translational misfolding of the Kv7.2 channel Urrutia, Janire Aguado, Alejandra Gomis-Perez, Carolina Muguruza-Montero, Arantza Ballesteros, Oscar R. Zhang, Jiaren Nuñez, Eider Malo, Covadonga Chung, Hee Jung Leonardo, Aritz Bergara, Aitor Villarroel, Alvaro BMC Biol Research Article BACKGROUND: The amino acid sequence of proteins generally carries all the necessary information for acquisition of native conformations, but the vectorial nature of translation can additionally determine the folding outcome. Such consideration is particularly relevant in human diseases associated to inherited mutations leading to structural instability, aggregation, and degradation. Mutations in the KCNQ2 gene associated with human epilepsy have been suggested to cause misfolding of the encoded Kv7.2 channel. Although the effect on folding of mutations in some domains has been studied, little is known of the way pathogenic variants located in the calcium responsive domain (CRD) affect folding. Here, we explore how a Kv7.2 mutation (W344R) located in helix A of the CRD and associated with hereditary epilepsy interferes with channel function. RESULTS: We report that the epilepsy W344R mutation within the IQ motif of CRD decreases channel function, but contrary to other mutations at this site, it does not impair the interaction with Calmodulin (CaM) in vitro, as monitored by multiple in vitro binding assays. We find negligible impact of the mutation on the structure of the complex by molecular dynamic computations. In silico studies revealed two orientations of the side chain, which are differentially populated by WT and W344R variants. Binding to CaM is impaired when the mutated protein is produced in cellulo but not in vitro, suggesting that this mutation impedes proper folding during translation within the cell by forcing the nascent chain to follow a folding route that leads to a non-native configuration, and thereby generating non-functional ion channels that fail to traffic to proper neuronal compartments. CONCLUSIONS: Our data suggest that the key pathogenic mechanism of Kv7.2 W344R mutation involves the failure to adopt a configuration that can be recognized by CaM in vivo but not in vitro. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12915-021-01040-1. BioMed Central 2021-05-21 /pmc/articles/PMC8138981/ /pubmed/34020651 http://dx.doi.org/10.1186/s12915-021-01040-1 Text en © The Author(s) 2021 https://creativecommons.org/licenses/by/4.0/Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) . The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/ (https://creativecommons.org/publicdomain/zero/1.0/) ) applies to the data made available in this article, unless otherwise stated in a credit line to the data.
spellingShingle Research Article
Urrutia, Janire
Aguado, Alejandra
Gomis-Perez, Carolina
Muguruza-Montero, Arantza
Ballesteros, Oscar R.
Zhang, Jiaren
Nuñez, Eider
Malo, Covadonga
Chung, Hee Jung
Leonardo, Aritz
Bergara, Aitor
Villarroel, Alvaro
An epilepsy-causing mutation leads to co-translational misfolding of the Kv7.2 channel
title An epilepsy-causing mutation leads to co-translational misfolding of the Kv7.2 channel
title_full An epilepsy-causing mutation leads to co-translational misfolding of the Kv7.2 channel
title_fullStr An epilepsy-causing mutation leads to co-translational misfolding of the Kv7.2 channel
title_full_unstemmed An epilepsy-causing mutation leads to co-translational misfolding of the Kv7.2 channel
title_short An epilepsy-causing mutation leads to co-translational misfolding of the Kv7.2 channel
title_sort epilepsy-causing mutation leads to co-translational misfolding of the kv7.2 channel
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8138981/
https://www.ncbi.nlm.nih.gov/pubmed/34020651
http://dx.doi.org/10.1186/s12915-021-01040-1
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