Specificity of charge-carrying residues in the voltage sensor of potassium channels

Christopher A Ahern; Richard Horn

doi:10.1085/jgp.200308993

Back

Specificity of charge-carrying residues in the voltage sensor of potassium channels

Journal article

Open access

Peer reviewed

Specificity of charge-carrying residues in the voltage sensor of potassium channels

Christopher A Ahern and Richard Horn

The Journal of general physiology, Vol.123(3), pp.205-216

03/2004

DOI: 10.1085/jgp.200308993

PMCID: PMC2217452

PMID: 14769847

Files and links (1)

url

https://doi.org/10.1085/jgp.200308993View

Published (Version of record) Open Access

Abstract

Positively charged voltage sensors of sodium and potassium channels are driven outward through the membrane's electric field upon depolarization. This movement is coupled to channel opening. A recent model based on studies of the KvAP channel proposes that the positively charged voltage sensor, christened the "voltage-sensor paddle", is a peripheral domain that shuttles its charged cargo through membrane lipid like a hydrophobic cation. We tested this idea by attaching charged adducts to cysteines introduced into the putative voltage-sensor paddle of Shaker potassium channels and measuring fractional changes in the total gating charge from gating currents. The only residues capable of translocating attached charges through the membrane-electric field are those that serve this function in the native channel. This remarkable specificity indicates that charge movement involves highly specialized interactions between the voltage sensor and other regions of the protein, a mechanism inconsistent with the paddle model.

Mutagenesis, Site-Directed

Potassium Channels, Voltage-Gated - chemistry

Potassium Channels, Voltage-Gated - physiology

Potassium Channels - physiology

Membrane Potentials - physiology

Cysteine - genetics

Potassium Channels - genetics

Potassium Channels - metabolism

Animals

Oocytes - physiology

Female

Potassium Channels - chemistry

Shaker Superfamily of Potassium Channels

Potassium Channels, Voltage-Gated - genetics

Details

Title: Subtitle: Specificity of charge-carrying residues in the voltage sensor of potassium channels
Creators: Christopher A Ahern - Department of Physiology, Jefferson Medical College, 1020 Locust Street, Philadelphia, PA 19107, USA
Richard Horn
Resource Type: Journal article
Publication Details: The Journal of general physiology, Vol.123(3), pp.205-216
DOI: 10.1085/jgp.200308993
PMID: 14769847
PMCID: PMC2217452
NLM abbreviation: J Gen Physiol
ISSN: 0022-1295
eISSN: 1540-7748
Publisher: United States
Grant note: R01 AR041691 / NIAMS NIH HHS AR41691 / NIAMS NIH HHS
Language: English
Date published: 03/2004
Academic Unit: Molecular Physiology and Biophysics; Iowa Neuroscience Institute
Record Identifier: 9984070159302771

Metrics

18 Record Views

71 Times Cited - Web of Science