Complex Voltage-Dependent Behavior of Single Unliganded Calcium-Sensitive Potassium Channels

The study and characterization of unliganded openings is of central significance for the elucidation of gating mechanisms for allosteric ligand-gated ion channels. Unliganded openings have been reported for many channel types, but their low open probability can make it difficult to study their kinet...

Full description

Saved in:
Bibliographic Details
Published in:Biophysical journal 2000-02, Vol.78 (2), p.761-772
Main Authors: Talukder, Gargi, Aldrich, Richard W.
Format: Article
Language:English
Subjects:
Animals
Calcium - metabolism
Electrophysiology
Ion Channel Gating
Kinetics
Large-Conductance Calcium-Activated Potassium Channels
Ligands
Mice
Models, Biological
Potassium Channels - metabolism
Potassium Channels, Calcium-Activated
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The study and characterization of unliganded openings is of central significance for the elucidation of gating mechanisms for allosteric ligand-gated ion channels. Unliganded openings have been reported for many channel types, but their low open probability can make it difficult to study their kinetics in detail. Because the large conductance calcium-activated potassium channel mSlo is sensitive to both intracellular calcium and to membrane potential, we have been able to obtain stable unliganded single-channel recordings of mSlo with relatively high opening probability. We have found that the single-channel gating behavior of mSlo is complex, with multiple open and closed states, even when no ligand is present. Our results rule out a Monod–Wyman–Changeux allosteric mechanism with a central voltage-dependent concerted step, and they support the existence of quaternary states with less than the full number of voltage sensors activated, as has been suggested by previous work involving measurements of gating currents.
ISSN:0006-3495
1542-0086
DOI:10.1016/S0006-3495(00)76634-3