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...
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Veröffentlicht in: | Pflügers Archiv 2001-09, Vol.442 (6), p.891-895 |
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Hauptverfasser: | , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | 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] |
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ISSN: | 0031-6768 1432-2013 |
DOI: | 10.1007/s004240100608 |