Mechanism and function of Kv channel targeting

Kv通道靶向的机制和功能

• 批准号: 8022827
• 负责人: CHEN GU
• 金额: $ 28.94万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-03-01 至 2014-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8022827
• 关键词: Action Potentials; Adaptor Signaling Protein; Adult; Adverse effects; Affect; Alternative Splicing; Ankyrins; Arrhythmia; Ataxia; Auditory; Axon; Binding; Biological Assay; Brain; Brain Diseases; Cells; Characteristics; Cognition; Complex; Computer Simulation; Data; Dendrites; Disease; Distal; Drug Delivery Systems; Electrophysiology (science); Epilepsy; Family; Fluorescence Recovery After Photobleaching; Fluorescence Resonance Energy Transfer; Frequencies; Functional disorder; Gene Mutation; Genes; Goals; Health; Hearing; Hippocampus (Brain); Human; Image; Imaging Techniques; Interneurons; Intervention; Kinetics; Knockout Mice; Life; Mediating; Membrane; Mitogen-Activated Protein Kinases; Modeling; Molecular; Molecular Biology; Motor Activity; Motor Neurons; Multiple Sclerosis; Mutagenesis; Mutation; Myocardium; Nerve Degeneration; Neuronal Plasticity; Neurons; Output; Pattern; Peptides; Pharmacologic Substance; Phosphorylation; Phosphorylation Site; Phosphotransferases; Physiological; Play; Potassium; Property; Protein Binding; Protein Biochemistry; RNA Splicing; Regulation; Research; Role; Signal Pathway; Signal Transduction; Site; Sleep Disorders; Small Interfering RNA; Specificity; Synaptic Transmission; Techniques; Testing; Variant; Vision; base; cell type; cellular imaging; design; innovation; insight; interdisciplinary approach; kinase inhibitor; member; motor disorder; nervous system disorder; neuronal cell body; neuronal excitability; novel; novel strategies; novel therapeutics; painful neuropathy; patch clamp; voltage

DESCRIPTION (provided by applicant): The long-term objectives are to understand how voltage-gated potassium (Kv) channels are localized into the proper subcellular compartments and how their localization affects neuronal excitability, and thus to develop new strategies for treating neurological diseases. Kv channel dysfunction causes diseases of brain, heart and muscle. Kv channels are the primary targets of pharmaceutical interventions to treat epilepsies, arrhythmias, neuropathic pain, and multiple sclerosis. Due to broad channel expression in many cell types, blockers or activators often bring severe side effects. Recent studies show that each Kv channel displays a distinct pattern of polarized targeting in neurons. It is the emerging theme that such polarized targeting affects neuronal excitability. However, the exact mechanism and function of Kv channel targeting remain mystery. Kv3 (Shaw) channels are unique among Kv channels in their high activation threshold and rapid deactivation kinetics. They are required for rapid spiking and involved in dendritic integration and transmitter release. Human adult-onset ataxia caused by mutations in Kv3.3 gene is a testament for their important functions. Reflecting their diverse functions, Kv3 channels display complex targeting patterns that are governed by unknown mechanisms. Our preliminary studies show that the two splice variants of Kv3.1 have identical channel properties but differentially regulate action potential firing. Interestingly, they differ in axon-dendrite targeting. Based on our preliminary data, we propose a new model that action potential firing is regulated by Kv3 channel targeting, which is in turn regulated by alternative splicing and protein phosphorylation. We will test three hypotheses in this model with three aims. By taking a multidisciplinary approach that includes electrophysiology, imaging, molecular biology and protein biochemistry techniques, we will determine whether: (Aim 1) polarized targeting of Kv channels is critical for action potential firing; (Aim 2) ankyrin G at the axon initial segment functions as a conditional barrier for Kv3 splice variants; (Aim 3) protein phosphorylation regulates Kv3 channel targeting and hence action potential firing. Our research will contribute to generate a new therapeutic strategy and reveal new drug targets for specifically controlling Kv3 channel functions in neurons, e.g. developing small peptides and kinase inhibitors as the treatment of ataxia, epilepsy and sleeping disorders. PUBLIC HEALTH RELEVANCE: Kv channels are the primary targets of pharmaceutical interventions to treat many diseases, in which the specificity of channel modulation is the key. Recent studies show that each Kv channel has its characteristic distribution pattern in nerve cells. Therefore, our project to understand how Kv channels are localized to regulate functions of nerve cells will contribute to generate novel strategies for treating diseases of the nervous systems.

描述（由申请人提供）：长期目标是了解电压门控钾（Kv）通道如何定位到适当的亚细胞区室以及它们的定位如何影响神经元兴奋性，从而开发治疗神经系统疾病的新策略。 Kv通道功能障碍会导致脑部、心脏和肌肉疾病。 Kv 通道是治疗癫痫、心律失常、神经性疼痛和多发性硬化症的药物干预的主要目标。由于多种细胞类型中的宽通道表达，阻断剂或激活剂通常会带来严重的副作用。最近的研究表明，每个 Kv 通道在神经元中显示出不同的极化靶向模式。这种极化靶向影响神经元兴奋性是一个新兴的主题。然而，Kv 通道靶向的确切机制和功能仍然是个谜。 Kv3 (Shaw) 通道在 Kv 通道中具有独特之处，因为其高激活阈值和快速失活动力学。它们是快速尖峰所必需的，并参与树突整合和递质释放。由 Kv3.3 基因突变引起的人类成人共济失调证明了其重要功能。 Kv3 通道反映了其多样化的功能，显示出由未知机制控制的复杂目标模式。我们的初步研究表明，Kv3.1 的两个剪接变体具有相同的通道特性，但对动作电位放电的调节不同。有趣的是，它们在轴突树突靶向方面有所不同。基于我们的初步数据，我们提出了一种新模型，即动作电位放电由 Kv3 通道靶向调节，而 Kv3 通道靶向又由选择性剪接和蛋白质磷酸化调节。我们将在该模型中测试三个假设，实现三个目标。通过采用包括电生理学、成像、分子生物学和蛋白质生物化学技术在内的多学科方法，我们将确定：（目标 1）Kv 通道的极化靶向对于动作电位放电至关重要； （目标 2）轴突起始段的锚蛋白 G 作为 Kv3 剪接变体的条件屏障发挥作用； （目标 3）蛋白质磷酸化调节 Kv3 通道靶向，从而调节动作电位放电。我们的研究将有助于产生新的治疗策略并揭示专门控制神经元中 Kv3 通道功能的新药物靶点，例如开发小肽和激酶抑制剂来治疗共济失调、癫痫和睡眠障碍。公共健康相关性：Kv 通道是治疗许多疾病的药物干预的主要目标，其中通道调节的特异性是关键。最近的研究表明，每个 Kv 通道在神经细胞中都有其特征性的分布模式。因此，我们了解 Kv 通道如何定位以调节神经细胞功能的项目将有助于产生治疗神经系统疾病的新策略。