Molecular determinants of hERG channel block
Molecular determinants of hERG channel block
复制标题
DOI：
10.1124/mol.105.020990
复制
发表时间：
2006-05-01
影响因子：
3.6
通讯作者：
Sanguinetti, MC
中科院分区：
文献类型：
--
作者：
Kamiya, K;Niwa, R;Sanguinetti, MC
药物诱导的心脏 hERG K+ 通道阻断会导致获得性长 QT 综合征。在这里，我们表征了两种低效药物（尼非卡兰和贝普地尔）和两种高效药物1-[2-(6-甲基-2-吡啶基)乙基]-4-(4-甲基磺酰基氨基苯甲酰基)哌啶（E-4031）和多非利特）阻断hERG的分子机制。通道在非洲爪蟾卵母细胞中表达，并使用两微电极电压钳技术测量电流。所有四种药物在 10 分钟无脉冲期后 20 秒去极化过程中逐渐将 hERG 电流降低至 0 mV，这与开放通道的优先阻断一致。观察到 D540K hERG 通道响应 -160 mV 脉冲而从阻断恢复，但野生型 hERG 通道未观察到，这表明所有四种药物通过激活门的关闭而被捕获在中央腔中。 hERG 通道阻断的分子决定因素是通过使用定点诱变方法来定义的。孔螺旋附近的三个残基（Thr623、Ser624 和 Val625）和 Ser6 中的四个残基（Gly648、Tyr652、Phe656 和 Val659）突变为丙氨酸，降低了通道对多非利特和 E-4031 阻断的敏感性，效果与之前报道的其他两种甲磺酰苯胺 (+)N-[1'-(6-cyano-) 的效果相同。 1,2,3,4-四氢-2(R)-萘基)-3,4-二氢-4(R)-羟基螺(2H-1-苯并吡喃-2,4'-哌啶)-6-基]甲磺酰胺]单盐酸盐(MK-499)和伊布利特。尼非卡兰对突变通道的作用相似，只是 V659A 保留正常敏感性而 I655A 通道敏感性较低。最后，孔螺旋附近的三个残基和 Ser6 结构域中的 Phe656 的突变减少了贝普地尔的通道阻断。我们得出的结论是，对于所有在开放状态下优先阻断 hERG 的药物来说，结合位点并不相同。
Drug-induced block of cardiac hERG K+ channels causes acquired long QT syndrome. Here, we characterized the molecular mechanism of hERG block by two low-potency drugs (Nifekalant and bepridil) and two high-potency drugs 1-[2-(6-methyl-2-pyridyl) ethyl]-4-(4-methylsulfonyl aminobenzoyl) piperidine (E-4031) and dofetilide). Channels were expressed in Xenopus laevis oocytes, and currents were measured using the two-microelectrode voltage-clamp technique. All four drugs progressively reduced hERG current during a 20-s depolarization to 0 mV after a 10-min pulse-free period, consistent with the preferential block of open channels. Recovery from block in response to pulses to -160 mV was observed for D540K hERG channels but not for wild-type hERG channels, suggesting that all four drugs are trapped in the central cavity by closure of the activation gate. The molecular determinants of hERG channel block were defined by using a site-directed mutagenesis approach. Mutation to alanine of three residues near the pore helix (Thr623, Ser624, and Val625) and four residues in Ser6 (Gly648, Tyr652, Phe656, and Val659) reduced channel sensitivity to block by dofetilide and E-4031, effects identical with those reported previously for two other methanesulfonanilides, (+)N-[1'-(6-cyano- 1,2,3,4-tetrahydro-2(R)-naphthalenyl)-3,4-dihydro-4(R)-hydroxyspiro(2H-1-benzopyran-2,4'-piperidin)-6-yl]methanesulfonamide] monohydrochloride (MK-499) and ibutilide. The effect of nifekalant on mutant channels was similar, except that V659A retained normal sensitivity and I655A channels were less sensitive. Finally, mutation of the three residues near the pore helix and Phe656 in the Ser6 domain reduced channel block by bepridil. We conclude that the binding site is not identical for all drugs that preferentially block hERG in the open state.