Cargando…

Mutational analysis to explore long-range allosteric couplings involved in a pentameric channel receptor pre-activation and activation

Pentameric ligand-gated ion channels (pLGICs) mediate chemical signaling through a succession of allosteric transitions that are yet not completely understood as intermediate states remain poorly characterized by structural approaches. In a previous study on the prototypic bacterial proton-gated cha...

Descripción completa

Detalles Bibliográficos
Autores principales: Lefebvre, Solène N, Taly, Antoine, Menny, Anaïs, Medjebeur, Karima, Corringer, Pierre-Jean
Formato: Online Artículo Texto
Lenguaje:English
Publicado: eLife Sciences Publications, Ltd 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8504973/
https://www.ncbi.nlm.nih.gov/pubmed/34590583
http://dx.doi.org/10.7554/eLife.60682
_version_ 1784581429553790976
author Lefebvre, Solène N
Taly, Antoine
Menny, Anaïs
Medjebeur, Karima
Corringer, Pierre-Jean
author_facet Lefebvre, Solène N
Taly, Antoine
Menny, Anaïs
Medjebeur, Karima
Corringer, Pierre-Jean
author_sort Lefebvre, Solène N
collection PubMed
description Pentameric ligand-gated ion channels (pLGICs) mediate chemical signaling through a succession of allosteric transitions that are yet not completely understood as intermediate states remain poorly characterized by structural approaches. In a previous study on the prototypic bacterial proton-gated channel GLIC, we generated several fluorescent sensors of the protein conformation that report a fast transition to a pre-active state, which precedes the slower process of activation with pore opening. Here, we explored the phenotype of a series of allosteric mutations, using simultaneous steady-state fluorescence and electrophysiological measurements over a broad pH range. Our data, fitted to a three-state Monod-Wyman-Changeux model, show that mutations at the subunit interface in the extracellular domain (ECD) principally alter pre-activation, while mutations in the lower ECD and in the transmembrane domain principally alter activation. We also show that propofol alters both transitions. Data are discussed in the framework of transition pathways generated by normal mode analysis (iModFit). It further supports that pre-activation involves major quaternary compaction of the ECD, and suggests that activation involves principally a reorganization of a ‘central gating region’ involving a contraction of the ECD β-sandwich and the tilt of the channel lining M2 helix.
format Online
Article
Text
id pubmed-8504973
institution National Center for Biotechnology Information
language English
publishDate 2021
publisher eLife Sciences Publications, Ltd
record_format MEDLINE/PubMed
spelling pubmed-85049732021-10-13 Mutational analysis to explore long-range allosteric couplings involved in a pentameric channel receptor pre-activation and activation Lefebvre, Solène N Taly, Antoine Menny, Anaïs Medjebeur, Karima Corringer, Pierre-Jean eLife Neuroscience Pentameric ligand-gated ion channels (pLGICs) mediate chemical signaling through a succession of allosteric transitions that are yet not completely understood as intermediate states remain poorly characterized by structural approaches. In a previous study on the prototypic bacterial proton-gated channel GLIC, we generated several fluorescent sensors of the protein conformation that report a fast transition to a pre-active state, which precedes the slower process of activation with pore opening. Here, we explored the phenotype of a series of allosteric mutations, using simultaneous steady-state fluorescence and electrophysiological measurements over a broad pH range. Our data, fitted to a three-state Monod-Wyman-Changeux model, show that mutations at the subunit interface in the extracellular domain (ECD) principally alter pre-activation, while mutations in the lower ECD and in the transmembrane domain principally alter activation. We also show that propofol alters both transitions. Data are discussed in the framework of transition pathways generated by normal mode analysis (iModFit). It further supports that pre-activation involves major quaternary compaction of the ECD, and suggests that activation involves principally a reorganization of a ‘central gating region’ involving a contraction of the ECD β-sandwich and the tilt of the channel lining M2 helix. eLife Sciences Publications, Ltd 2021-09-30 /pmc/articles/PMC8504973/ /pubmed/34590583 http://dx.doi.org/10.7554/eLife.60682 Text en © 2021, Lefebvre et al https://creativecommons.org/licenses/by/4.0/This article is distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use and redistribution provided that the original author and source are credited.
spellingShingle Neuroscience
Lefebvre, Solène N
Taly, Antoine
Menny, Anaïs
Medjebeur, Karima
Corringer, Pierre-Jean
Mutational analysis to explore long-range allosteric couplings involved in a pentameric channel receptor pre-activation and activation
title Mutational analysis to explore long-range allosteric couplings involved in a pentameric channel receptor pre-activation and activation
title_full Mutational analysis to explore long-range allosteric couplings involved in a pentameric channel receptor pre-activation and activation
title_fullStr Mutational analysis to explore long-range allosteric couplings involved in a pentameric channel receptor pre-activation and activation
title_full_unstemmed Mutational analysis to explore long-range allosteric couplings involved in a pentameric channel receptor pre-activation and activation
title_short Mutational analysis to explore long-range allosteric couplings involved in a pentameric channel receptor pre-activation and activation
title_sort mutational analysis to explore long-range allosteric couplings involved in a pentameric channel receptor pre-activation and activation
topic Neuroscience
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8504973/
https://www.ncbi.nlm.nih.gov/pubmed/34590583
http://dx.doi.org/10.7554/eLife.60682
work_keys_str_mv AT lefebvresolenen mutationalanalysistoexplorelongrangeallostericcouplingsinvolvedinapentamericchannelreceptorpreactivationandactivation
AT talyantoine mutationalanalysistoexplorelongrangeallostericcouplingsinvolvedinapentamericchannelreceptorpreactivationandactivation
AT mennyanais mutationalanalysistoexplorelongrangeallostericcouplingsinvolvedinapentamericchannelreceptorpreactivationandactivation
AT medjebeurkarima mutationalanalysistoexplorelongrangeallostericcouplingsinvolvedinapentamericchannelreceptorpreactivationandactivation
AT corringerpierrejean mutationalanalysistoexplorelongrangeallostericcouplingsinvolvedinapentamericchannelreceptorpreactivationandactivation