A590T mutation in KCNQ1 C-terminal helix D decreases IKs channel trafficking and function but not Yotiao interaction.
A590T mutation in KCNQ1 C-terminal helix D decreases IKs channel trafficking and function but not Yotiao interaction.
复制标题
KCNQ1 C 端螺旋 D 中的 A590T 突变会降低 IK 通道的运输和功能，但不会降低 Yotiao 的相互作用。
DOI：
10.1016/j.yjmcc.2014.03.019
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发表时间：
2014
影响因子：
5
通讯作者：
Nishida N.
中科院分区：
文献类型：
--
作者：
Kinoshita K;Komatsu T;Nishide K;Hata Y;Hisajima N;Takahashi H;Kimoto K;Aonuma K;Tushima E;Tabata T;Yoshida T;Mori H;Nishida K;Yamaguchi Y;Ichida F;Fukurotani K;Inoue H;Nishida N.
KCNQ1 编码电压门控通道的 α 亚基，介导心脏慢延迟整流 K+电流 (IK)。在这里，我们报告了在一名 39 岁轻度 QT 延长女性中发现的编码 A590T 突变 [KCNQ1(A590T)] 的 KCNQ1 等位基因。 A590 位于 KCNQ1 的 C 端 α 螺旋区域，介导亚基四聚化、膜运输以及与 Yotiao 的相互作用。已知这种相互作用是 cAMP 正确调节 IK 所必需的。由于之前的研究报道 A590 附近的突变会损害 IKs 通道表面表达和功能，因此我们检查了 A590T 突变是否以及如何影响 IKs 通道。 HEK-293T 细胞的电生理测量表明，A590T 突变导致 IK 密度降低和通道激活的电流-电压关系右移。免疫细胞化学和免疫印迹分析显示 KCNQ1(A590T) 亚基的细胞表面表达减少，并通过野生型 KCNQ1 [KCNQ1(WT)] 亚基的共表达来挽救。此外，KCNQ1（A590T）亚基与Yotiao相互作用，并且具有与KCNQ1（WT）亚基相当的cAMP反应性。这些发现表明，KCNQ1 亚基的 A590 通过一种独立于 Yotiao 相互作用的新机制，在维持通道表面表达和功能方面发挥着重要作用。
KCNQ1encodes the α subunit of the voltage-gated channel that mediates the cardiac slow delayed rectifier K+current (IKs). Here, we report aKCNQ1allele encoding an A590T mutation [KCNQ1(A590T)] found in a 39-year-old female with a mild QT prolongation. A590 is located in the C-terminal α helical region of KCNQ1 that mediates subunit tetramerization, membrane trafficking, and interaction with Yotiao. This interaction is known to be required for the proper modulation ofIKsby cAMP. Since previous studies reported that mutations in the vicinity of A590 impairIKschannel surface expression and function, we examined whether and how the A590T mutation affects theIKschannel. Electrophysiological measurements in HEK-293T cells showed that the A590T mutation caused a reduction inIKsdensity and a right-shift of the current–voltage relation of channel activation. Immunocytochemical and immunoblot analyses showed the reduced cell surface expression of KCNQ1(A590T) subunit and its rescue by coexpression of the wild-type KCNQ1 [KCNQ1(WT)] subunit. Moreover, KCNQ1(A590T) subunit interacted with Yotiao and had a cAMP-responsiveness comparable to that of KCNQ1(WT) subunit. These findings indicate that the A590 of KCNQ1 subunit plays important roles in the maintenance of channel surface expression and function via a novel mechanism independent of interaction with Yotiao.