| Literature DB >> 17597584 |
Bjorn C Knollmann1, Syevda Sirenko, Qi Rong, Alexander N Katchman, Mathew Casimiro, Karl Pfeifer, Steven N Ebert.
Abstract
It has been suggested that Kcne1 subunits are required for adrenergic regulation of Kcnq1 potassium channels. However, in adult mouse hearts, which do not express Kcne1, loss of Kcnq1 causes a Long QT phenotype during adrenergic challenge, raising the possibility that native Kcnq1 currents exist and are adrenergically regulated even in absence of Kcne1. Here, we used immunoblotting and immunohistochemical staining to show that Kcnq1 protein is present in adult mouse hearts. Voltage-clamp experiments demonstrated that Kcnq1 contributes to a steady-state outward current (I(SS)) in wild-type (Kcnq1(+/+)) ventricular myocytes during isoproterenol stimulation, resulting in a significant 7.1% increase in I(SS) density (0.43+/-0.16 pA/pF, p <0.05, n =15), an effect that was absent in Kcnq1-deficient (Kcnq1(-/-)) myocytes (-0.14+/-0.13 pA/pF, n =17). These results demonstrate for the first time that Kcnq1 protein is expressed in adult mouse hearts where it contributes to a beta-adrenergic-induced component of I(SS) that does not require co-assembly with Kcne1.Entities:
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Year: 2007 PMID： 17597584 PMCID： PMC2025686 DOI： 10.1016/j.bbrc.2007.06.038
Source DB: PubMed Journal: Biochem Biophys Res Commun ISSN： 0006-291X Impact factor: 3.575