hERG1a突变H70R对hERG1a单源四聚体和hERG1a/hERG1b二源四聚体通道功能的影响

doi:10.3969/j.issn.1006-7795.2022.05.013

摘要/Abstract

摘要： 目的本研究拟探索KCNH2编码心肌细胞快速延迟整流钾离子通道(rapidly activating delayed rectifier K⁺ channel, I_Kr)α亚基(the human ether-à-go-go-related gene,hERG)转录产物——hERG1a特有突变H70R对hERG1a单源四聚体通道(I_hERG1a)及hERG1a/ hERG1b二源四聚体通道(I_{hERG1a/hERG1b})功能的影响,明确是否存在差异。方法以脂质体转染技术通过HEK293细胞表达可疑致病突变。应用全细胞膜片钳技术分别记录I_hERG1a、I_{hERG1a/hERG1b}电流。结果 H70R对I_{hERG1a/ hERG1b}电流密度抑制较I_hERG1a更为显著(61% vs 42%;P<0.001);且至稳态激活曲线左移,显著降低半激活电压(P<0.05);H70R对I_hERG1a和I_{hERG1a/hERG1b}通道灭活动力学无显著影响(P>0.05),I_{hERG1a/hERG1b}较I_hERG1a灭活显著加快(P>0.05)。结论 H70R对I_hERG1a及I_{hERG1a/hERG1b}通道功能影响趋势一致,但对I_{hERG1a/hERG1b}通道电流抑制更为显著,I_{hERG1a/hERG1b}较I_hERG1a灭活显著加快,提示在hERG相关临床致病突变研究中应重视I_{hERG1a/hERG1b}通道功能的改变。

关键词: 快速延迟整流钾离子通道, 长QT综合征, H70R, hERG1a, hERG1b

Abstract: Objective To investigate the electrophysiological effects of hERG1a specific N terminal mutation (H70R) on current (I_Kr) carried by co-expressed hERG1a/1b channels. Methods H70R was introduced in pcDNA3.1 (hERG1a) by site-directed mutagenesis, and transient transfection was applied to express hERG in HEK293 cell. Whole cell patch clamp analysis of the HEK293 cell with expressing wild type and mutant channel was used to investigate the molecular and electrophysiological mechanism. Results H70R showed I_Kr current decrease in both homologues and heterologous hERG channel, the effect on hERG1a/1b channels was more significant than that of hERG1a expressed alone. H70R caused steady-state activation curve to shift to the left and decreased V_1/2 in both homomeric and heteromeric hERG channel. Different from early report, H70R showed no effect on I_Krdeactivation; however, hERG1a/1b channels showed significantly accelerated deactivation. Conclusions hERG1a (H70R) caused a decreased current in both homomeric and heteromeric hERG channel, but a more significant suppression on heteromeric hERG. It suggested that we should pay more attention to the co-expressed I_hERG1a/1b channels in the clinical study of hERG-related channel mutations.

Key words: rapid delayed rectifier potassium channel, Long QT Syndrome, H70R, hERG1a, hERG1b

中图分类号:

R541.7

冯莉, 杨佳雪, 李新, 贾长琪, 蒋晨曦. hERG1a突变H70R对hERG1a单源四聚体和hERG1a/hERG1b二源四聚体通道功能的影响[J]. 首都医科大学学报, 2022, 43(5): 747-753.

Feng Li, Yang Jiaxue, Li Xin, Jia Changqi, Jiang Chenxi. Functional change of hERG1a mutation H70R on hERG1a homomeric current and hERG1a/1b heteromeric currents[J]. Journal of Capital Medical University, 2022, 43(5): 747-753.

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