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The hERG potassium channel intrinsic ligand regulates N- and C-terminal interactions and channel closure

Human ether-à-go-go–related gene (hERG, KCNH2) voltage-activated potassium channels are critical for cardiac excitability. hERG channels have characteristic slow closing (deactivation), which is auto-regulated by a direct interaction between the N-terminal Per-Arnt-Sim (PAS) domain and the C-termina...

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Autores principales: Codding, Sara J., Trudeau, Matthew C.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Rockefeller University Press 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6445578/
https://www.ncbi.nlm.nih.gov/pubmed/30425124
http://dx.doi.org/10.1085/jgp.201812129
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author Codding, Sara J.
Trudeau, Matthew C.
author_facet Codding, Sara J.
Trudeau, Matthew C.
author_sort Codding, Sara J.
collection PubMed
description Human ether-à-go-go–related gene (hERG, KCNH2) voltage-activated potassium channels are critical for cardiac excitability. hERG channels have characteristic slow closing (deactivation), which is auto-regulated by a direct interaction between the N-terminal Per-Arnt-Sim (PAS) domain and the C-terminal cyclic nucleotide binding homology domain (CNBHD). hERG channels are not activated by the binding of extrinsic cyclic nucleotide ligands, but rather bind an “intrinsic ligand” that is composed of residues 860–862 within the CNBHD and mimics a cyclic nucleotide. The intrinsic ligand is located at the PAS–CNBHD interface, but its mechanism of action in hERG is not well understood. Here we use whole-cell patch-clamp electrophysiology and FRET spectroscopy to examine how the intrinsic ligand regulates gating. To carry out this work, we coexpress PAS (a PAS domain fused to cyan fluorescent protein) in trans with hERG “core” channels (channels with a deletion of the PAS domain fused to citrine fluorescent protein). The PAS domain in trans with hERG core channels has slow (regulated) deactivation, like that of WT hERG channels, as well as robust FRET, which indicates there is a direct functional and structural interaction of the PAS domain with the channel core. In contrast, PAS in trans with hERG F860A core channels has intermediate deactivation and intermediate FRET, indicating perturbation of the PAS domain interaction with the CNBHD. Furthermore, PAS in trans with hERG L862A core channels, or PAS in trans with hERG F860G,L862G core channels, has fast (nonregulated) deactivation and no measurable FRET, indicating abolition of the PAS and CNBHD interaction. These results indicate that the intrinsic ligand is necessary for the functional and structural interaction between the PAS domain and the CNBHD, which regulates the characteristic slow deactivation gating in hERG channels.
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spelling pubmed-64455782019-10-01 The hERG potassium channel intrinsic ligand regulates N- and C-terminal interactions and channel closure Codding, Sara J. Trudeau, Matthew C. J Gen Physiol Research Articles Human ether-à-go-go–related gene (hERG, KCNH2) voltage-activated potassium channels are critical for cardiac excitability. hERG channels have characteristic slow closing (deactivation), which is auto-regulated by a direct interaction between the N-terminal Per-Arnt-Sim (PAS) domain and the C-terminal cyclic nucleotide binding homology domain (CNBHD). hERG channels are not activated by the binding of extrinsic cyclic nucleotide ligands, but rather bind an “intrinsic ligand” that is composed of residues 860–862 within the CNBHD and mimics a cyclic nucleotide. The intrinsic ligand is located at the PAS–CNBHD interface, but its mechanism of action in hERG is not well understood. Here we use whole-cell patch-clamp electrophysiology and FRET spectroscopy to examine how the intrinsic ligand regulates gating. To carry out this work, we coexpress PAS (a PAS domain fused to cyan fluorescent protein) in trans with hERG “core” channels (channels with a deletion of the PAS domain fused to citrine fluorescent protein). The PAS domain in trans with hERG core channels has slow (regulated) deactivation, like that of WT hERG channels, as well as robust FRET, which indicates there is a direct functional and structural interaction of the PAS domain with the channel core. In contrast, PAS in trans with hERG F860A core channels has intermediate deactivation and intermediate FRET, indicating perturbation of the PAS domain interaction with the CNBHD. Furthermore, PAS in trans with hERG L862A core channels, or PAS in trans with hERG F860G,L862G core channels, has fast (nonregulated) deactivation and no measurable FRET, indicating abolition of the PAS and CNBHD interaction. These results indicate that the intrinsic ligand is necessary for the functional and structural interaction between the PAS domain and the CNBHD, which regulates the characteristic slow deactivation gating in hERG channels. Rockefeller University Press 2019-04-01 2018-11-13 /pmc/articles/PMC6445578/ /pubmed/30425124 http://dx.doi.org/10.1085/jgp.201812129 Text en This is a work of the U.S. Government and is not subject to copyright protection in the United States. Foreign copyrights may apply. http://www.rupress.org/terms/https://creativecommons.org/licenses/by-nc-sa/4.0/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 4.0 International license, as described at https://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Research Articles
Codding, Sara J.
Trudeau, Matthew C.
The hERG potassium channel intrinsic ligand regulates N- and C-terminal interactions and channel closure
title The hERG potassium channel intrinsic ligand regulates N- and C-terminal interactions and channel closure
title_full The hERG potassium channel intrinsic ligand regulates N- and C-terminal interactions and channel closure
title_fullStr The hERG potassium channel intrinsic ligand regulates N- and C-terminal interactions and channel closure
title_full_unstemmed The hERG potassium channel intrinsic ligand regulates N- and C-terminal interactions and channel closure
title_short The hERG potassium channel intrinsic ligand regulates N- and C-terminal interactions and channel closure
title_sort herg potassium channel intrinsic ligand regulates n- and c-terminal interactions and channel closure
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6445578/
https://www.ncbi.nlm.nih.gov/pubmed/30425124
http://dx.doi.org/10.1085/jgp.201812129
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