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Control of Inward Rectifier K Channel Activity by Lipid Tethering of Cytoplasmic Domains
Interactions between nontransmembrane domains and the lipid membrane are proposed to modulate activity of many ion channels. In Kir channels, the so-called “slide-helix” is proposed to interact with the lipid headgroups and control channel gating. We examined this possibility directly in a cell-free...
Autores principales: | , , , |
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Formato: | Texto |
Lenguaje: | English |
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The Rockefeller University Press
2007
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2151642/ https://www.ncbi.nlm.nih.gov/pubmed/17698595 http://dx.doi.org/10.1085/jgp.200709764 |
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author | Enkvetchakul, Decha Jeliazkova, Iana Bhattacharyya, Jaya Nichols, Colin G. |
author_facet | Enkvetchakul, Decha Jeliazkova, Iana Bhattacharyya, Jaya Nichols, Colin G. |
author_sort | Enkvetchakul, Decha |
collection | PubMed |
description | Interactions between nontransmembrane domains and the lipid membrane are proposed to modulate activity of many ion channels. In Kir channels, the so-called “slide-helix” is proposed to interact with the lipid headgroups and control channel gating. We examined this possibility directly in a cell-free system consisting of KirBac1.1 reconstituted into pure lipid vesicles. Cysteine substitution of positively charged slide-helix residues (R49C and K57C) leads to loss of channel activity that is rescued by in situ restoration of charge following modification by MTSET(+) or MTSEA(+), but not MTSES(−) or neutral MMTS. Strikingly, activity is also rescued by modification with long-chain alkyl-MTS reagents. Such reagents are expected to partition into, and hence tether the side chain to, the membrane. Systematic scanning reveals additional slide-helix residues that are activated or inhibited following alkyl-MTS modification. A pattern emerges whereby lipid tethering of the N terminus, or C terminus, of the slide-helix, respectively inhibits, or activates, channel activity. This study establishes a critical role of the slide-helix in Kir channel gating, and directly demonstrates that physical interaction of soluble domains with the membrane can control ion channel activity. |
format | Text |
id | pubmed-2151642 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2007 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-21516422008-03-01 Control of Inward Rectifier K Channel Activity by Lipid Tethering of Cytoplasmic Domains Enkvetchakul, Decha Jeliazkova, Iana Bhattacharyya, Jaya Nichols, Colin G. J Gen Physiol Communications Interactions between nontransmembrane domains and the lipid membrane are proposed to modulate activity of many ion channels. In Kir channels, the so-called “slide-helix” is proposed to interact with the lipid headgroups and control channel gating. We examined this possibility directly in a cell-free system consisting of KirBac1.1 reconstituted into pure lipid vesicles. Cysteine substitution of positively charged slide-helix residues (R49C and K57C) leads to loss of channel activity that is rescued by in situ restoration of charge following modification by MTSET(+) or MTSEA(+), but not MTSES(−) or neutral MMTS. Strikingly, activity is also rescued by modification with long-chain alkyl-MTS reagents. Such reagents are expected to partition into, and hence tether the side chain to, the membrane. Systematic scanning reveals additional slide-helix residues that are activated or inhibited following alkyl-MTS modification. A pattern emerges whereby lipid tethering of the N terminus, or C terminus, of the slide-helix, respectively inhibits, or activates, channel activity. This study establishes a critical role of the slide-helix in Kir channel gating, and directly demonstrates that physical interaction of soluble domains with the membrane can control ion channel activity. The Rockefeller University Press 2007-09 /pmc/articles/PMC2151642/ /pubmed/17698595 http://dx.doi.org/10.1085/jgp.200709764 Text en Copyright © 2007, The Rockefeller University Press 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 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/). |
spellingShingle | Communications Enkvetchakul, Decha Jeliazkova, Iana Bhattacharyya, Jaya Nichols, Colin G. Control of Inward Rectifier K Channel Activity by Lipid Tethering of Cytoplasmic Domains |
title | Control of Inward Rectifier K Channel Activity by Lipid Tethering of Cytoplasmic Domains |
title_full | Control of Inward Rectifier K Channel Activity by Lipid Tethering of Cytoplasmic Domains |
title_fullStr | Control of Inward Rectifier K Channel Activity by Lipid Tethering of Cytoplasmic Domains |
title_full_unstemmed | Control of Inward Rectifier K Channel Activity by Lipid Tethering of Cytoplasmic Domains |
title_short | Control of Inward Rectifier K Channel Activity by Lipid Tethering of Cytoplasmic Domains |
title_sort | control of inward rectifier k channel activity by lipid tethering of cytoplasmic domains |
topic | Communications |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2151642/ https://www.ncbi.nlm.nih.gov/pubmed/17698595 http://dx.doi.org/10.1085/jgp.200709764 |
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