MOLECULAR DETERMINANTS OF POTASSIUM CHANNEL DRUG BLOCK

描述(申请人摘要)：这项研究的长期目标是 了解心脏兴奋性的分子基础。在本建议书中 研究人员将研究电压门控K的分子决定因素 用抗心律失常药物和局麻药阻断通道。电压门控 钾通道在控制心脏兴奋性和 复极是许多新的抗心律失常药物的分子靶点 探员们。研究人员将利用被认为是克隆的亚基 对自然心脏电流(Kv1.5、Kv4.2、HERG、KvLQT1)有贡献。 越来越多的证据表明，通道的分子结构 蛋白质复合体包括功能改变的辅助亚基(β 亚基，水貂)，这可能会影响药物结合。假设是 测试包括S6片段中的特定孔残留物参与 开放通道阻滞剂的结合。此外，调查人员将 测试疏水相互作用是否决定亲和力和 药物阻断的立体选择性。此外，他们还将测试氨基 孔隙衬里区段中的酸度差异解释了异构体的特异性 抗心律失常药物的亲和力。他们将讨论是否 抗心律失常药物利用保守的受体部位失活 通过测试内口的相互作用来检测β亚基 毛孔。最后，他们将测试KcLQT1的内在药理是否 当它与水貂亚单位共同组装时被改变 土生土长的流浪汉。在这些研究中，他们将使用现代技术 的分子生物学来修饰通道结构和各种贴片 用于测试特定功能变化的钳夹技术。结果将会是 根据航道的数学和热力学模型进行解释 禁闭和毒品行动。这些研究将涉及分子决定因素。 药物阻断和药物与激活和失活门的相互作用。 从这个项目中获得的信息将扩大我们对 这些重要渠道的分子药理学，最终可能 结果提高了对心律失常的机制和 开发更好的抗心律失常治疗方法。

DESCRIPTION (Applicant's Abstract): The long term goal of this research is to understand the molecular basis of cardiac excitability. In this proposal the investigators will study molecular determinants of voltage-gated K+ channel block by antiarrhythmic drugs and local anesthetics. Voltage-gated K+ channels play a crucial role in controlling cardiac excitability and repolarization and are the molecular target for many new antiarrhythmic agents. The investigators will utilize cloned subunits that are considered to contribute to native cardiac currents (Kv1.5, Kv4.2, HERG, KvLQT1). Increasing evidence indicates that the molecular architecture of the channel protein complex includes function-altering accessory subunits (beta subunits, minK) which may impact on drug binding. The hypotheses to be tested include that specific pore residues in the S6 segment are involved in binding of open channel blocking drugs. Furthermore, the investigators will test whether hydrophobic interactions determine affinity and stereoselectivity of drug block. In addition, they will test whether amino acid differences in the pore lining segments explain isoform-specific affinities for antiarrhythmic drugs. They will address whether antiarrhythmic drugs utilize a conserved receptor site for inactivating beta-subunits by testing for mutual interactions in the inner mouth of the pore. Finally, they will test whether the intrinsic pharmacology of KcLQT1 is altered when it co-assembles with the minK subunit to reconstitute the native current Iks. In these studies they will use contemporary techniques of molecular biology to modify channel structure and a variety of patch clamp techniques to test for specific functional changes. The results will be interpreted in terms of mathematical and thermodynamic models for channel gating and drug action. These studies will address molecular determinants of drug block and drug interactions with activation and inactivation gates . The information gained from this project will expand our knowledge of the molecular pharmacology of these important channels, which may ultimately result in improved understanding of mechanisms of arrhythmias and the development of better antiarrhythmic treatments.