The Journal of General Physiology
Avanti Polar Lipids, Inc.
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents
This Article
Right arrow Full Text
Right arrow Full Text (PDF, 272K)
Right arrow PPT slides of all figures
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JGP
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Loots, E.
Right arrow Articles by Isacoff, E.Y.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Loots, E.
Right arrow Articles by Isacoff, E.Y.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Facebook   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?
© The Rockefeller University Press, 0022-1295/1998//377/ $5.00
Journal of General Physiology, Volume 112, Number 4, 1998

Article

Protein Rearrangements Underlying Slow Inactivation of the Shaker K+ Channel

E. Loots and E.Y. Isacoff

From the Department of Molecular & Cell Biology, University of California, Berkeley, Berkeley, California 94720-3200

Voltage-dependent ion channels transduce changes in the membrane electric field into protein rearrangements that gate their transmembrane ion permeation pathways. While certain molecular elements of the voltage sensor and gates have been identified, little is known about either the nature of their conformational rearrangements or about how the voltage sensor is coupled to the gates. We used voltage clamp fluorometry to examine the voltage sensor (S4) and pore region (P-region) protein motions that underlie the slow inactivation of the Shaker K+ channel. Fluorescent probes in both the P-region and S4 changed emission intensity in parallel with the onset and recovery of slow inactivation, indicative of local protein rearrangements in this gating process. Two sequential rearrangements were observed, with channels first entering the P-type, and then the C-type inactivated state. These forms of inactivation appear to be mediated by a single gate, with P-type inactivation closing the gate and C-type inactivation stabilizing the gate's closed conformation. Such a stabilization was due, at least in part, to a slow rearrangement around S4 that stabilizes S4 in its activated transmembrane position. The fluorescence reports of S4 and P-region fluorophore are consistent with an increased interaction of the voltage sensor and inactivation gate upon gate closure, offering insight into how the voltage-sensing apparatus is coupled to a channel gate.

Key Words: inactivation • fluorescence • K+ channel • pore • S4

Address correspondence to E.Y. Isacoff, Department of Molecular & Cell Biology, University of California, Berkeley, 271 Life Science Addition, Berkeley, CA 94720-3200. Fax: 510-643-6791; E-mail: ehud{at}uclink.berkeley.edu

Abbreviations: F-V, fluorescence–voltage; G-V, conductance–voltage; P-region, pore region; TMRM, tetramethylrhodamine maleimide


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Facebook Facebook   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?


This article has been cited by other articles:


Home page
 JGPHome page
E. Perozo
Shedding Light on Voltage-dependent Gating
J. Gen. Physiol., October 1, 1998; 112(4): 373 - 376.
[Full Text] [PDF]


  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents