Dependence of I Ks biophysical properties on the expression system

The delayed rectifier potassium current I ^sub Ks^ is important for repolarization of the cardiac action potential. In heart I ^sub Ks^ is a heteromeric channel composed of KCNQ1 (KvLQT1) and minK (KCNE1, IsK). Here we show that the KCNQ1/minK interaction is influenced by the expression system. Co-e...

Full description

Saved in:
Bibliographic Details
Published in:Pflügers Archiv 2001-09, Vol.442 (6), p.891-895
Main Authors: Seebohm, G, Lerche, C, Busch, A, Bachmann, A
Format: Article
Language:English
Subjects:
Dependence
Rodents
Citations: 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 delayed rectifier potassium current I ^sub Ks^ is important for repolarization of the cardiac action potential. In heart I ^sub Ks^ is a heteromeric channel composed of KCNQ1 (KvLQT1) and minK (KCNE1, IsK). Here we show that the KCNQ1/minK interaction is influenced by the expression system. Co-expression of KCNQ1 and minK in Xenopus oocytes resulted in potassium currents comparable to endogenous guinea pig cardiac I ^sub Ks^ in terms of temperature dependency and activation kinetics. In contrast, heterologous expression of I ^sub Ks^ in CHO cells revealed currents with a markedly different biophysical behavior. The sensitivity to the extracellular potassium concentration, temperature dependency and kinetics differ qualitatively. Potentially there is an endogenous component that affects I ^sub Ks^ which does not appear in all expression systems.[PUBLICATION ABSTRACT]
ISSN:0031-6768
1432-2013
DOI:10.1007/s004240100608