Modulation of BK channel voltage gating by different auxiliary β subunits.
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| Title: | Modulation of BK channel voltage gating by different auxiliary β subunits. |
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| Authors: | Contreras, Gustavo F.1,2, Neely, Alan1, Alvarez, Osvaldo1,3, Gonzalez, Carlos1 carlos.gonzalez1@uv.cl, Latorre, Ramon1 ramon.latorre@uv.cl |
| Source: | Proceedings of the National Academy of Sciences of the United States of America. 11/13/2012, Vol. 109 Issue 46, p18991-18996. 6p. |
| Subjects: | Xenopus, Potassium channels, Phenotypes, Ovum, Metabolic regulation |
| Abstract: | Calciumand voltage-activated potassium channels (BK) are regulated by a multiplicity of signals. The prevailing view is that different BK gating mechanisms converge to determine channel opening and that these gating mechanisms are allosterically coupled. In most instances the pore forming a subunit of BK is associated with one of four alternative β subunits that appear to target specific gating mechanisms to regulate the channel activity. In particular, β1 stabilizes the active configuration of the BK voltage sensor having a large effect on BK Ca2+ sensitivity. To determine the extent to which β subunits regulate the BK voltage sensor, we measured gating currents induced by the pore-forming BK α subunit alone and with the different β subunits expressed in Xenopus oocytes (β1, β2IR, β3, and β4). We found that β1, β2, and β4 stabilize the BK voltage sensor in the active conformation. β3 has no effect on voltage sensor equilibrium. In addition, β4 decreases the apparent number of charges per voltage sensor. The decrease in the charge associated with the voltage sensor in a β4 channels explains most of their biophysical properties. For channels composed of the a subunit alone, gating charge increases slowly with pulse duration as expected if a significant fraction of this charge develops with a time course comparable to that of K+ current activation. In the presence of β~1, β2, and β4 this slow component develops in advance of and much more rapidly than ion current activation, suggesting that BK channel opening proceeds in two steps. [ABSTRACT FROM AUTHOR] |
| Copyright of Proceedings of the National Academy of Sciences of the United States of America is the property of National Academy of Sciences and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 84040273 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Modulation of BK channel voltage gating by different auxiliary β subunits. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Contreras%2C+Gustavo+F%2E%22">Contreras, Gustavo F.</searchLink><relatesTo>1,2</relatesTo><br /><searchLink fieldCode="AR" term="%22Neely%2C+Alan%22">Neely, Alan</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Alvarez%2C+Osvaldo%22">Alvarez, Osvaldo</searchLink><relatesTo>1,3</relatesTo><br /><searchLink fieldCode="AR" term="%22Gonzalez%2C+Carlos%22">Gonzalez, Carlos</searchLink><relatesTo>1</relatesTo><i> carlos.gonzalez1@uv.cl</i><br /><searchLink fieldCode="AR" term="%22Latorre%2C+Ramon%22">Latorre, Ramon</searchLink><relatesTo>1</relatesTo><i> ramon.latorre@uv.cl</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Proceedings+of+the+National+Academy+of+Sciences+of+the+United+States+of+America%22">Proceedings of the National Academy of Sciences of the United States of America</searchLink>. 11/13/2012, Vol. 109 Issue 46, p18991-18996. 6p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Xenopus%22">Xenopus</searchLink><br /><searchLink fieldCode="DE" term="%22Potassium+channels%22">Potassium channels</searchLink><br /><searchLink fieldCode="DE" term="%22Phenotypes%22">Phenotypes</searchLink><br /><searchLink fieldCode="DE" term="%22Ovum%22">Ovum</searchLink><br /><searchLink fieldCode="DE" term="%22Metabolic+regulation%22">Metabolic regulation</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Calciumand voltage-activated potassium channels (BK) are regulated by a multiplicity of signals. The prevailing view is that different BK gating mechanisms converge to determine channel opening and that these gating mechanisms are allosterically coupled. In most instances the pore forming a subunit of BK is associated with one of four alternative β subunits that appear to target specific gating mechanisms to regulate the channel activity. In particular, β1 stabilizes the active configuration of the BK voltage sensor having a large effect on BK Ca2+ sensitivity. To determine the extent to which β subunits regulate the BK voltage sensor, we measured gating currents induced by the pore-forming BK α subunit alone and with the different β subunits expressed in Xenopus oocytes (β1, β2IR, β3, and β4). We found that β1, β2, and β4 stabilize the BK voltage sensor in the active conformation. β3 has no effect on voltage sensor equilibrium. In addition, β4 decreases the apparent number of charges per voltage sensor. The decrease in the charge associated with the voltage sensor in a β4 channels explains most of their biophysical properties. For channels composed of the a subunit alone, gating charge increases slowly with pulse duration as expected if a significant fraction of this charge develops with a time course comparable to that of K+ current activation. In the presence of β~1, β2, and β4 this slow component develops in advance of and much more rapidly than ion current activation, suggesting that BK channel opening proceeds in two steps. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Proceedings of the National Academy of Sciences of the United States of America is the property of National Academy of Sciences and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1073/pnas.1216953109 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 6 StartPage: 18991 Subjects: – SubjectFull: Xenopus Type: general – SubjectFull: Potassium channels Type: general – SubjectFull: Phenotypes Type: general – SubjectFull: Ovum Type: general – SubjectFull: Metabolic regulation Type: general Titles: – TitleFull: Modulation of BK channel voltage gating by different auxiliary β subunits. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Contreras, Gustavo F. – PersonEntity: Name: NameFull: Neely, Alan – PersonEntity: Name: NameFull: Alvarez, Osvaldo – PersonEntity: Name: NameFull: Gonzalez, Carlos – PersonEntity: Name: NameFull: Latorre, Ramon IsPartOfRelationships: – BibEntity: Dates: – D: 13 M: 11 Text: 11/13/2012 Type: published Y: 2012 Identifiers: – Type: issn-print Value: 00278424 Numbering: – Type: volume Value: 109 – Type: issue Value: 46 Titles: – TitleFull: Proceedings of the National Academy of Sciences of the United States of America Type: main |
| ResultId | 1 |
