Drug therapy targeted to the voltage-gated sodium channel

应用程序的总体目标是了解本地 麻醉/抗心律失常药物(LA)与心脏电压门控钠(Na)通道(NaV1.5)。这个 实验将使用野生型(WT)和定点突变的钠通道异源表达 哺乳动物细胞和卵母细胞结合钠通道孔道的分子模拟。目标1.LA 毛孔中的结合位置。我们假设LA与DIV-Phe1759的结合直接与DIIIS6相互作用 DIIIS6和DIVS6在开放/灭活通道中的紧密堆积相互作用或残基 导致DIIIS4稳定的配置。在这个目标中，我们建议进一步探索药物 DIV和DIII中S6‘S与钠通道内孔的相互作用及其稳定化 根据这一假说，我们将确定DiI-Leu1461在偶联中的作用 从DIV到DIII。目的2：快速失活与LA亲和力之间的联系。我们假设FAST的结合 灭活盖是稳定高亲和力药物/通道相互作用的必要条件。为了达到这个目标，我们建议 通过关联LA的大小和灵活性来确定失活对高亲和力LA块的贡献有多快 和抗惊厥药物对其EC50‘S突变通道的快速灭活作用 灭活盖及最近报道的利多卡因诱导的Brugada综合征的基础 NAV1.5通道病，V232I+L1308F。目标3.LA与闭合通道和早期步骤的相互作用 激活。我们假设由S6段形成的钠通道孔的打开是被动的， 而药物与封闭通道的结合适度地稳定了这种构型。在此基础上， 假设我们将通过S6之间的交联半胱氨酸取代来确定束交叉处的残基 细分市场。

The overall aim of the application is to understand the fundamental basis of the interaction of local anesthetic/antiarrhythmic drugs (LA) with the cardiac voltage-gated sodium (Na) channel (NaV1.5). The experiments will use wild-type (WT) and site-directed mutant Na channels heterologously expressed in mammalian cells and oocytes combined with molecular modeling of the Na channel pore. Aim 1. The LA binding site in the pore. We hypothesize that binding of LA to DIV-Phe1759 directly interacts with DIIIS6 residues or indirectly by close-packed interactions between DIIIS6 and DIVS6 in the open/inactivated channel configuration that results in stabilization of the DIIIS4. In this aim we propose to further explore drug interactions with the Na channel inner pore between S6's in DIV and DIII and stabilization of their corresponding S4's. In pursuance of this hypothesis we will determine the role of DIII-Leu1461 in the coupling of DIV to DIII. Aim 2: The link between fast inactivation and LA affinity. We hypothesize that binding of the fast inactivation lid is obligatory for stabilizing the high-affinity drug/channel interaction. In this aim we propose to determine how fast inactivation contributes to high affinity LA block by correlating the size and flexibility of LA and anticonvulsant drugs to their EC50's in mutant channels with fast inactivation removed by mutagenesis of the inactivation lid and by investigating the basis of the recently reported lidocaine-induced Brugada Syndrome NaV1.5 channelopathy, V232I+L1308F. Aim 3. LA interactions with the closed channel and with early steps in activation. We hypothesize that the opening of the Na channel pore formed by the S6 segments is passive, and that drug binding to the closed channel modestly stabilizes this configuration. In pursuance of this hypothesis we will determine the residues at the bundle crossing by crosslinking Cys substitutions between S6 segments.