| Properties of deactivation gating currents in Shaker channels. | |
| | |
MedLine Citation:
|
PMID: 21354387 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
The charge versus voltage relation of voltage-sensor domains shifts in the voltage axis depending on the initial voltage. Here we show that in nonconducting W434F Shaker K(+) channels, a large portion of this charge-voltage shift is apparent due to a dramatic slowing of the deactivation gating currents, Ig(D) (with τ up to 80 ms), which develops with a time course of ∼1.8 s. This slowing in Ig(D) adds up to the slowing due to pore opening and is absent in the presence of 4-aminopyridine, a compound that prevents the last gating step that leads to pore opening. A remaining 10-15 mV negative shift in the voltage dependence of both the kinetics and the charge movement persists independently of the depolarizing prepulse duration and remains in the presence of 4-aminopyridine, suggesting the existence of an intrinsic offset in the local electric field seen by activated channels. We propose a new (to our knowledge) kinetic model that accounts for these observations. |
| | |
Authors:
|
Jérôme J Lacroix; Alain J Labro; Francisco Bezanilla |
Related Documents
:
|
17888407 - Imbalance between cam kinase ii and calcineurin activities impairs caffeine-induced cal... 20694017 - Inhibitory actions of mibefradil on steroidogenesis in mouse leydig cells: involvement ... 20448467 - Pcaps, possible regulators of ptdinsp signals on plasma membrane. 1868137 - Calcium-dependent and calcium-independent gelatinolytic proteinase activities of the ra... 1920117 - Mechanisms of ionophore-induced stimulation of renin secretion with special reference t... 7563017 - Electrical currents generated by a partially purified na/ca exchanger from lobster musc... |
Publication Detail:
|
Type: Journal Article; Research Support, N.I.H., Extramural |
Journal Detail:
|
Title: Biophysical journal Volume: 100 ISSN: 1542-0086 ISO Abbreviation: Biophys. J. Publication Date: 2011 Mar |
Date Detail:
|
Created Date: 2011-02-28 Completed Date: 2011-06-02 Revised Date: 2012-09-24 |
Medline Journal Info:
|
Nlm Unique ID: 0370626 Medline TA: Biophys J Country: United States |
Other Details:
|
Languages: eng Pagination: L28-30 Citation Subset: IM |
Copyright Information:
|
Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved. |
Affiliation:
|
Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois, USA. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
4-Aminopyridine
/
pharmacology Animals Ion Channel Gating / drug effects, physiology* Kinetics Models, Biological* Shaker Superfamily of Potassium Channels / metabolism* |
| Grant Support | |
ID/Acronym/Agency:
|
GM030376/GM/NIGMS NIH HHS |
| Chemical | |
Reg. No./Substance:
|
0/Shaker Superfamily of Potassium Channels; 504-24-5/4-Aminopyridine |
| Comments/Corrections | |
Comment In:
|
Biophys J. 2011 Jul 20;101(2):512-4; discussion 515-6
[PMID:
21767505
]
|
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Cell shape and substrate rigidity both regulate cell stiffness.
Next Document: A unified model of transcription elongation: what have we learned from single-molecule experiments?