Molecular mechanisms for small molecule compounds targeting SK/IK channels

靶向 SK/IK 通道的小分子化合物的分子机制

基本信息

批准号：
9313902
负责人：
JI-FANG ZHANG
金额：
$ 30.81万
依托单位：
THOMAS JEFFERSON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-08-01 至 2019-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9313902
关键词：
Academia Address Adverse effects Affinity Alcohol abuse Amino Acids Amyotrophic Lateral Sclerosis Ataxia Autistic Disorder Binding Binding Proteins Binding Sites Biochemistry Biophysics Calmodulin Cardiovascular Diseases Cardiovascular system Chemicals Chemosensitization Clinical Clinical Trials Complex Data Development Disease Disease model Drug Binding Site Drug Design EF Hand Motifs Electrophysiology (science)Explosion Family Future Generations Generations Heart Atrium Hypertension Industry Ion Channel Knowledge Legal patent Lobe Mediating Membrane Membrane Lipids Molecular Molecular Biology Molecular Conformation Molecular Mechanisms of Action Neoplasm Metastasis Neuraxis Neurodegenerative Disorders Paper Pharmaceutical Preparations Phosphatidylinositol 4,5-Diphosphate Physiological Play Positioning Attribute Potassium Channel Property Publications Research Role Signal Transduction Spinal Muscular Atrophy Structure Substance abuse problem Testing Therapeutic Tissues Ursidae Family Ventricular Fibrillation Voltage-Gated Potassium Channel Withdrawal Work base cancer cell cell motility design drug development drug structure experimental study in vivo inhibitor/antagonist new therapeutic target novel prevent protein complex protein protein interaction prototype public health relevance sensor small molecule structural biology therapeutic target

项目摘要

DESCRIPTION (provided by applicant): Ca2+‐activated potassium channels, such as small‐ and intermediate‐conductance K+ channels (SK and IK), are widely expressed in excitable tissues. They play pivotal roles in regulating membrane excitability by Ca2+. Unlike voltage‐gated K+ channels, activation of SK/IK channels is achieved exclusively by Ca2+. Calmodulin (CaM), tethered to the channel C‐terminus, serves as the high‐affinity Ca2+ sensor. Four EF‐hands, two located at the CaM N‐terminus (N‐lobe) and the other two at the C‐terminus (C‐lobe), are the high affinity Ca2+ binding sites. The Ca2+‐mediated interaction between CaM and the CaM binding domain (CaMBD) activates the channel. In addition to their physiological roles, SK/IK channels have been implicated in clinical abnormalities. Consequently, a tremendous effort has been devoted to developing small molecules targeting SK/IK channels in both academia and industry. 1‐ethyl‐2‐benzimidazolinone (1‐EBIO) is such a prototype that potentiates the SK/IK channel activity and effectively decreases the membrane excitability. Studies have shown that the 1‐ EBIO compounds are beneficial in disease models of the central nervous system and the cardiovascular system. In general, however, the 1‐EBIO compounds suffer from drawbacks, such as lack of selectivity, which hamper their potential for clinical trials. A key contributing factor is lack of knowledge of how the 1‐EBIO compounds interact with their binding site and achieve their effects on SK/IK channels. Until the publication of our recent papers, it was not known where these compounds might interact with SK/IK channels. The molecular properties of the drug binding site remain unclear and it is not known how the 1‐EBIO compounds work, or how these compounds achieve their selectivity. To uncover the molecular properties of the drug binding site for these compounds and understand the molecular mechanisms for the actions of the 1‐EBIO compounds, we will use integrated approaches of structural biology, molecular biology, biochemistry biophysics and electrophysiology. Specifically, we will focus on the following issues: (1) Characterization of the binding site for the 1‐EBIO compounds and molecular mechanisms that contribute to selectivity of the 1‐EBIO compounds for SK/IK channels. 1‐EBIO compounds over different types of SK/IK channels. (2) Molecular mechanisms by which the 1‐EBIO compounds potentiate SK/IK channels. (3) Molecular mechanisms by which the 1‐EBIO compounds inhibit SK/IK channels. Results from the proposed work will provide the molecular properties of the drug binding site for the 1‐EBIO compounds. The results will fill in the current knowledge gap regarding how these compounds modulate SK/IK channel activity (potentiation and inhibition). The knowledge will facilitate development of future generations of therapeutics targeting SK/IK channels by structure‐based drug design/development. Broadly, our results will help develop compounds targeting other CaM‐target protein complexes involved in Ca2+ dependent signaling as well as new drugs targeting membrane lipids beyond the ion channel field.

描述（由申请人提供）：Ca2+ 激活的钾通道，例如小电导和中电导 K+ 通道（SK 和 IK），在兴奋性组织中广泛表达，与电压不同，它们在调节膜兴奋性方面发挥着关键作用。在门控 K+ 通道中，SK/IK 通道的激活仅由钙调蛋白 (CaM) 实现，钙调蛋白 (CaM) 与通道 C 末端相连，充当通道。高亲和力 Ca2+ 传感器。四个 EF 手，两个位于 CaM N 末端（N 叶），另外两个位于 C 末端（C 叶），是高亲和力 Ca2+ 结合位点。 CaM 和 CaM 结合域 (CaMBD) 之间介导的相互作用激活通道除了其生理作用外，SK/IK 通道还与临床异常有关。学术界和工业界正在开发针对 SK/IK 通道的小分子。研究表明，1-乙基-2-苯并咪唑啉酮 (1-EBIO) 是一种增强 SK/IK 通道活性并有效降低膜兴奋性的原型。 1-EBIO 化合物对中枢神经系统和心血管系统的疾病模型有益，但一般来说，1-EBIO 化合物存在一些问题，例如缺乏选择性。阻碍其临床试验潜力的一个关键因素是缺乏对 1-EBIO 化合物如何与其结合位点相互作用以及如何对 SK/IK 通道产生影响的了解。在我们最近的论文中，尚不清楚这些化合物可能在何处与 SK/IK 通道相互作用。药物结合位点的分子特性仍不清楚，也不知道 1-EBIO 化合物如何发挥作用，也不知道这些化合物如何实现其选择性。为了揭示这些化合物的药物结合位点的分子特性并了解 1-EBIO 化合物作用的分子机制，我们将使用结构生物学、分子生物学、生物化学生物物理学和电生理学的综合方法。专注于下列问题： (1) 特征 1-EBIO 化合物的结合位点以及有助于 1-EBIO 化合物对 SK/IK 通道的选择性的分子机制。 1-EBIO 化合物相对于不同类型的 SK/IK 通道会增强 SK/IK 通道。 ) 1-EBIO 化合物抑制 SK/IK 通道的分子机制。拟议工作的结果将提供药物结合位点的分子特性。 1-EBIO 化合物。这些结果将填补目前有关这些化合物如何调节 SK/IK 通道活性（增强和抑制）的知识空白。这些知识将有助于开发基于结构的药物靶向 SK/IK 通道的疗法。总体而言，我们的研究结果将有助于开发针对参与 Ca2+ 依赖性信号传导的其他 CaM 靶蛋白复合物的化合物，以及针对离子通道领域之外的膜脂的新药物。