Partial restoration of the long QT syndrome associated KCNQ1 A341V mutant by the KCNE1 β-subunit.
Partial restoration of the long QT syndrome associated KCNQ1 A341V mutant by the KCNE1 β-subunit.
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DOI：
10.1016/j.bbagen.2011.07.018
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发表时间：
2011-12
影响因子：
3
通讯作者：
Kwok, Wai-Meng
中科院分区：
文献类型：
--
作者：
Mikuni, Ikuomi;Torres, Carlos G.;Bienengraeber, Martin W.;Kwok, Wai-Meng
缓慢激活的延迟整流钾电流 (IK) 的成孔 KCNQ1 亚基中的 A341V 突变是长 QT 综合征的常见形式的基础，并且与异常严重的表型相关。然而，关于临床观察到的表型的潜在机制存在争议。我们利用心脏细胞系研究了 A341V 在心脏环境中的生物物理特征，特别是 KCNE1 β 亚基的影响。记录瞬时转染的 HL-1 细胞（一种心肌细胞系）的全细胞电流。突变体KCNQ1和KCNE1是通过定点诱变构建的。 A341V 突变体单独表达时会产生非功能性通道。当与野生型KCNE1共表达时，A341V产生缓慢的激活电流，与野生型KCNQ1+KCNE1相比，电流密度更小，激活速率更慢，激活曲线有去极化偏移。共聚焦显微镜证实了 GFP 标记的 A341V 的表面表达，表明存在功能缺陷的蛋白质。 KCNE1 中的 T58A 突变导致 A341V 的功能恢复失效。在杂合条件下，A341V+KCNQ1+KCNE1 的表达减少，但并未消除 A341V+KCNE1 中观察到的电生理变化。还观察到 A341V 的显着负面影响。动作电位模拟显示 A341V 突变会导致心律失常。 KCNE1 β 亚基部分拯救了无功能的 A341V 突变体，其电生理特性与野生型 IK 不同。 A341V 表型的严重性可能是由于 IK 的显着抑制与生物物理特征的改变相结合。
The A341V mutation in the pore-forming KCNQ1 subunit of the slowly activating delayed-rectifier potassium current (IKs) underlies a common form of the long QT syndrome, and is associated with an unusually severe phenotype. However, there is controversy regarding the underlying mechanism responsible for the clinically observed phenotype. We investigated the biophysical characteristics of A341V in a cardiac environment by utilizing a cardiac cell line, and in particular the impact of the KCNE1 β -subunit. Whole-cell current were recorded from transiently transfected HL-1 cells, a cardiac cell line. Mutant KCNQ1 and KCNE1 were constructed by site-directed mutagenesis. The A341V mutant resulted in a non-functional channel when expressed alone. When co-expressed with wild type KCNE1, A341V produced a slowly activating current, with a smaller current density, slower rates of activation, and a depolarized shift in its activation curve compared to the wild type KCNQ1+KCNE1. Confocal microscopy confirmed the surface expression of GFP-tagged A341V, suggesting a functionally defective protein. A T58A mutation in KCNE1 abolished functional restoration of A341V. Under heterozygous conditions, the expression of A341V+KCNQ1+KCNE1 reduced but did not abolish the electrophysiological changes observed in A341V+KCNE1. A dominant negative effect of A341V was also observed. Action potential simulations revealed that the A341V mutation is arrhythmogenic. The KCNE1 β-subunit partially rescued the non-functional A341V mutant, with electrophysiological properties distinct from the wild type IKs. The severity of the A341V phenotype may be due to a combination of a significant suppression of the IKs with altered biophysical characteristics.
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影响因子：
37.8
作者：
Crotti, Lia;Monti, Maria Cristina;George, Alfred L., Jr.
通讯作者：
George, Alfred L., Jr.
影响因子：
5.5
作者：
Panaghie, G;Tai, KK;Abbott, GW
通讯作者：
Abbott, GW
影响因子：
6.1
作者：
Anastasakis, Aris;Kotta, Christina-Maria;Stefanadis, Christodoulos
通讯作者：
Stefanadis, Christodoulos
影响因子：
10.8
作者：
Boulet, Inge R.;Raes, Adam L.;Snyders, Dirk J.
通讯作者：
Snyders, Dirk J.
影响因子：
20.1
作者：
Seebohm, G;Pusch, M;Sanguinetti, MC
通讯作者：
Sanguinetti, MC