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The Polyamine Binding Site in Inward Rectifier K(+) Channels
Strongly inwardly rectifying potassium channels exhibit potent and steeply voltage-dependent block by intracellular polyamines. To locate the polyamine binding site, we have examined the effects of polyamine blockade on the rate of MTSEA modification of cysteine residues strategically substituted in...
Autores principales: | , , |
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Formato: | Texto |
Lenguaje: | English |
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The Rockefeller University Press
2006
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2151516/ https://www.ncbi.nlm.nih.gov/pubmed/16606689 http://dx.doi.org/10.1085/jgp.200509467 |
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author | Kurata, Harley T. Marton, Laurence J. Nichols, Colin G. |
author_facet | Kurata, Harley T. Marton, Laurence J. Nichols, Colin G. |
author_sort | Kurata, Harley T. |
collection | PubMed |
description | Strongly inwardly rectifying potassium channels exhibit potent and steeply voltage-dependent block by intracellular polyamines. To locate the polyamine binding site, we have examined the effects of polyamine blockade on the rate of MTSEA modification of cysteine residues strategically substituted in the pore of a strongly rectifying Kir channel (Kir6.2[N160D]). Spermine only protected cysteines substituted at a deep location in the pore, between the “rectification controller” residue (N160D in Kir6.2, D172 in Kir2.1) and the selectivity filter, against MTSEA modification. In contrast, blockade with a longer synthetic polyamine (CGC-11179) also protected cysteines substituted at sites closer to the cytoplasmic entrance of the channel. Modification of a cysteine at the entrance to the inner cavity (169C) was unaffected by either spermine or CGC-11179, and spermine was clearly “locked” into the inner cavity (i.e., exhibited a dramatically slower exit rate) following modification of this residue. These data provide physical constraints on the spermine binding site, demonstrating that spermine stably binds at a deep site beyond the “rectification controller” residue, near the extracellular entrance to the channel. |
format | Text |
id | pubmed-2151516 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2006 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-21515162008-01-17 The Polyamine Binding Site in Inward Rectifier K(+) Channels Kurata, Harley T. Marton, Laurence J. Nichols, Colin G. J Gen Physiol Articles Strongly inwardly rectifying potassium channels exhibit potent and steeply voltage-dependent block by intracellular polyamines. To locate the polyamine binding site, we have examined the effects of polyamine blockade on the rate of MTSEA modification of cysteine residues strategically substituted in the pore of a strongly rectifying Kir channel (Kir6.2[N160D]). Spermine only protected cysteines substituted at a deep location in the pore, between the “rectification controller” residue (N160D in Kir6.2, D172 in Kir2.1) and the selectivity filter, against MTSEA modification. In contrast, blockade with a longer synthetic polyamine (CGC-11179) also protected cysteines substituted at sites closer to the cytoplasmic entrance of the channel. Modification of a cysteine at the entrance to the inner cavity (169C) was unaffected by either spermine or CGC-11179, and spermine was clearly “locked” into the inner cavity (i.e., exhibited a dramatically slower exit rate) following modification of this residue. These data provide physical constraints on the spermine binding site, demonstrating that spermine stably binds at a deep site beyond the “rectification controller” residue, near the extracellular entrance to the channel. The Rockefeller University Press 2006-05 /pmc/articles/PMC2151516/ /pubmed/16606689 http://dx.doi.org/10.1085/jgp.200509467 Text en Copyright © 2006, 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 | Articles Kurata, Harley T. Marton, Laurence J. Nichols, Colin G. The Polyamine Binding Site in Inward Rectifier K(+) Channels |
title | The Polyamine Binding Site in Inward Rectifier K(+) Channels |
title_full | The Polyamine Binding Site in Inward Rectifier K(+) Channels |
title_fullStr | The Polyamine Binding Site in Inward Rectifier K(+) Channels |
title_full_unstemmed | The Polyamine Binding Site in Inward Rectifier K(+) Channels |
title_short | The Polyamine Binding Site in Inward Rectifier K(+) Channels |
title_sort | polyamine binding site in inward rectifier k(+) channels |
topic | Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2151516/ https://www.ncbi.nlm.nih.gov/pubmed/16606689 http://dx.doi.org/10.1085/jgp.200509467 |
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