Liu Li, Tian Jinwen, Lu Caiyi, Chen Xi, Fu Yicheng, Xu Bin, Zhu Chao, Sun Yanmei, Zhang Yu, Zhao Ying, Li Yang
Department of Cardiology, General Hospital of People's Liberation ArmyBeijing, China; The Third Department of Internal Medicine, Beijing Municipal Corps Hospital of Chinese People's Armed Police ForceBeijing, China.
Department of Cardiology, General Hospital of People's Liberation Army Beijing, China.
Front Physiol. 2016 Dec 27;7:650. doi: 10.3389/fphys.2016.00650. eCollection 2016.
Mutations in cause long QT syndrome type 2 which is characterized by a prolonged QT interval on electrocardiogram and predisposition to life-threatening ventricular tachyarrhythmia, syncope, and sudden death. induces trafficking defects of channel protein from Golgi to the plasma membrane and results in a dominant negative suppression of current density. As an accessory β subunit, promotes migration from Golgi to cellular membrane. In this study, we investigated the rescue effect of in a mutation of . Transfection was performed into HEK293 cells. Patch clamp technique, western blotting analyses and confocal microscopic examination were used. Results showed that had a significantly enhanced effect on mutation current. The increase of current was largest at : of 1:3. Confocal images showed co-expressing and could cause a substantial up-regulated membrane protein (155 kDa) expression. Expression of membrane protein accumulated markedly with increasing ratio of :. defective mutant could be restored by both and lower temperature (27°C), which suggested that the lower temperature could be the favorable circumstances for the rescue function of . In this study, we successfully set up "the action potential" on the HEK 293 cells by genetically engineered to express Kir2.1, Nav1.5, and Kv11.1, wherein on reaching over an excitation threshold by current injection. The results suggested that could shorten action potential duration which was prolonged by . These findings described electrophysiological characteristics of the LQT2 syndrome mutation and regulation by accessory protein , and provided a clue about LQT2 and relative rescue mechanism.
某基因的突变会导致2型长QT综合征，其特征为心电图上QT间期延长，且易发生危及生命的室性快速心律失常、晕厥和猝死。该基因诱导通道蛋白从高尔基体向质膜的转运缺陷，并导致对电流密度的显性负性抑制。作为辅助β亚基，某蛋白促进某蛋白从高尔基体向细胞膜的迁移。在本研究中，我们研究了某蛋白对某基因突变的挽救作用。将其转染到人胚肾293（HEK293）细胞中。采用膜片钳技术、蛋白质免疫印迹分析和共聚焦显微镜检查。结果表明，某蛋白对某基因突变电流有显著增强作用。在某比例时电流增加最大：比例为1:3。共聚焦图像显示，共表达某蛋白和某蛋白可导致膜蛋白（155 kDa）表达大幅上调。膜蛋白的表达随着某蛋白与某蛋白比例的增加而显著积累。某缺陷突变体可通过某蛋白和较低温度（27°C）恢复，这表明较低温度可能是某蛋白发挥挽救功能的有利条件。在本研究中，我们通过基因工程使HEK 293细胞表达Kir2.1、Nav1.5和Kv11.1成功建立了“动作电位”，其中通过电流注入达到兴奋阈值。结果表明，某蛋白可缩短由某蛋白延长的动作电位持续时间。这些发现描述了LQT2综合征突变某基因的电生理特征以及辅助蛋白某蛋白的调节作用，并为LQT2及其相关挽救机制提供了线索。
