MinK endows the I(Ks) potassium channel pore with sensitivity to internal tetraethylammonium

Federico Sesti, Kwok Keung Tai, Steve A.N. Goldstein

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

I(Ks) channels are heteromeric complexes of pore-forming KvLQT1 subunits and pore-associated MinK subunits. Channels formed only of KvLQT1 subunits vary from I(Ks) channels in their gating kinetics, single-channel conductance, and ion selectivity. Here we show that I(Ks) channels are more sensitive to blockade by internal tetraethylammonium ion (TEA) than KvLQT1 channels. Inhibition by internal TEA is shown to proceed by a simple bimolecular interaction in the I(Ks) conduction pathway. Application of a noise-variance strategy suggests that MinK enhances blockade by increasing the dwell time of TEA on its pore site from ~70 to 370 μs. Mutation of consecutive residues across the single transmembrane segment of MinK identifies positions that alter TEA blockade of I(Ks) channels. MinK is seen to determine the pharmacology of I(Ks) channels in addition to establishing their biophysical attributes.

Original languageEnglish (US)
Pages (from-to)1369-1378
Number of pages10
JournalBiophysical journal
Volume79
Issue number3
DOIs
StatePublished - Jan 1 2000
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biophysics

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