Role of the S3-S4 linker in Shaker potassium channel activation

Rajesh Mathur, Jie Zheng, Yangyang Yan, Fred J. Sigworth

Research output: Contribution to journalArticle

55 Citations (Scopus)

Abstract

Structural models of voltage-gated channels suggest that flexibility of the S3-S4 linker region may be important in allowing the S4 region to undergo large conformational changes in its putative voltage-sensing function. We report here the initial characterization of 18 mutations in the S3-S4 linker of the Shaker channel, including deletions, insertions, charge changes, substitution of prolines, and chimeras replacing the 25-residue Shaker linker with 7- or 9-residue sequences from Shab, Shaw, or Shal. As measured in Xenopus oocytes with a two-microelectrode voltage clamp, each mutant construct yielded robust currents. Changes in the voltage dependence of activation were small, with activation voltage shifts 13 mV or less. Substitution of linkers from the slowly activating Shab and Shaw channels resulted in a three- to fourfold slowing of activation and deactivation. It is concluded that the S3-S4 linker is unlikely to participate in a large conformational change during channel activation. The linker, which in some channel subfamilies has highly conserved sequences, may however be a determinant of activation kinetics in potassium channels, as previously has been suggested in the case of calcium channels.

Original languageEnglish (US)
Pages (from-to)191-199
Number of pages9
JournalJournal of General Physiology
Volume109
Issue number2
DOIs
StatePublished - Feb 1997
Externally publishedYes

Fingerprint

Shaker Superfamily of Potassium Channels
Conserved Sequence
Potassium Channels
Structural Models
Microelectrodes
Calcium Channels
Xenopus
Proline
Oocytes
Mutation

Keywords

  • mutagenesis
  • potassium channel
  • protein sequence
  • voltage clamp

ASJC Scopus subject areas

  • Physiology

Cite this

Role of the S3-S4 linker in Shaker potassium channel activation. / Mathur, Rajesh; Zheng, Jie; Yan, Yangyang; Sigworth, Fred J.

In: Journal of General Physiology, Vol. 109, No. 2, 02.1997, p. 191-199.

Research output: Contribution to journalArticle

Mathur, Rajesh ; Zheng, Jie ; Yan, Yangyang ; Sigworth, Fred J. / Role of the S3-S4 linker in Shaker potassium channel activation. In: Journal of General Physiology. 1997 ; Vol. 109, No. 2. pp. 191-199.
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