Neuronal Kv2.1 Potassium Channels as Organizers of Somatic L-Type Calcium Channel Microdomains

神经元 Kv2.1 钾通道作为体细胞 L 型钙通道微域的组织者

• 批准号: 10355490
• 负责人: Luis F Santana
• 金额: $ 46.03万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10355490
• 关键词: Ablation; Action Potentials; Animals; Biophysics; Brain; CREB1 gene; Cell membrane; Consensus; Coupled; Coupling; Data; Dendrites; Dendritic Spines; Dependence; Disease; Endoplasmic Reticulum; Event; Functional disorder; Gene Expression; Genes; Genetic Transcription; Health; Hippocampus (Brain); Image; Intervention; Ion Channel; L-Type Calcium Channels; Lead; Mediating; Mediator of activation protein; Membrane; Mental disorders; Modeling; Molecular; Molecular Analysis; Mutation; Neurodegenerative Disorders; Neurodevelopmental Disorder; Neurons; Phenotype; Play; Population; Potassium Channel; Property; Proteins; Proteomics; Regulation; Role; Ryanodine Receptors; Shapes; Signal Pathway; Signal Transduction; Site; Structure; Synaptic plasticity; System; Testing; Transcript; Vertebral column; Work; base; experimental study; gene therapy; high resolution imaging; multimodality; mutant; nervous system disorder; neuronal cell body; neurotransmission; novel; protein complex; response; skills; transcription factor; voltage; voltage gated channel

L-type Ca2+ channels (LTCCs) play a fundamental role in brain neurons as mediators of diverse Ca2+ signaling events. LTCCs on neuronal somata play a unique and crucial role in regulating Ca2+-dependent gene expression. A salient feature of LTCCs is that their activity is regulated by clustering through cooperative gating of clustered channels. Their clustering also localizes them to specialized Ca2+ signaling microdomains within which they functionally couple to Ca2+-dependent proteins that transduce the impact of LTCC-mediated Ca2+ entry to specific Ca2+ signaling pathways. Through their canonical function as K+ conducting voltage-gated channels, somatic Kv2.1 channels play critical roles in the regulation of action potentials, with a subsequent impact on LTCC activity. The general consensus is that the functions of LTCCs and Kv2.1 channels in neurons are otherwise largely independent from one another. Our recent work challenges this view. We discovered a novel and unexpected nonconducting role for Kv2.1 in physically regulating the organization of neuronal LTCCs, enhancing their activity and impacting their localization in specific microdomains. These exciting new results lead to a novel model that in brain neurons, Kv2.1 plays dual roles, one as a canonical K+ channel shaping the intrinsic membrane properties of neurons, and the other a nonconducting physical role to cluster LTCCs to enhance their activity and localize them in Ca2+ signaling microdomains. The combination of the complementary backgrounds and skill sets of the Timmer and Santana labs allows us to implement a multi-scale systems approach that involves the use of cellular, molecular, biophysical, imaging, gene editing and whole-animal approaches to rigorously investigate the molecular mechanisms whereby Kv2.1 impacts LTCC organization, and the consequences to LTCC function and neuronal signaling. The project has three specific aims, which are to determine how selectively eliminating 1) Kv2.1 expression, 2) Kv2.1 clustering, and 3) the ability of Kv2.1 to enhance LTCC clustering impacts somatic LTCC localization and function, Ca2+-induced Ca2+ release or sparks, and LTCC-dependent transcript factor activation. The proposed studies have the potential of transforming our understanding of how neuronal ion channels are regulated and how this impacts Ca2+ signaling in health and when altered in disease.

L 型 Ca2+ 通道 (LTCC) 作为多种 Ca2+ 信号传导的介质，在大脑神经元中发挥着重要作用 事件。神经元体细胞上的 LTCC 在调节 Ca2+ 依赖性基因表达中发挥着独特而关键的作用。 LTCC 的一个显着特征是它们的活动通过集群的协作门控进行集群调节。 渠道。它们的聚集还使它们定位于专门的 Ca2+ 信号传导微域，在这些微域中它们 与 Ca2+ 依赖性蛋白功能性偶联，将 LTCC 介导的 Ca2+ 进入的影响转导至特定的 Ca2+ 信号通路。通过其作为 K+ 传导电压门控通道的典型功能，体细胞 Kv2.1 通道在动作电位的调节中发挥关键作用，从而对 LTCC 活动产生后续影响。 普遍的共识是神经元中 LTCC 和 Kv2.1 通道的功能在很大程度上是不同的 彼此独立。我们最近的工作挑战了这一观点。我们发现了一本小说和意想不到的 Kv2.1 在神经元 LTCC 组织的物理调节中的非传导作用，增强其活性 并影响它们在特定微域中的定位。这些令人兴奋的新结果催生了一种新颖的模型 在大脑神经元中，Kv2.1 发挥双重作用，其一是作为塑造内膜的典型 K+ 通道 神经元的特性，另一个是不导电的物理作用，使 LTCC 聚集以增强其活性 并将它们定位在 Ca2+ 信号微域中。互补的背景和技能的结合 Timmer 和 Santana 实验室的集合使我们能够实施一种多尺度系统方法，其中涉及 使用细胞、分子、生物物理、成像、基因编辑和整体动物方法来严格 研究 Kv2.1 影响 LTCC 组织的分子机制及其后果 LTCC 功能和神经信号传导。该项目有三个具体目标，即确定如何 选择性消除 1) Kv2.1 表达、2) Kv2.1 聚类和 3) Kv2.1 增强 LTCC 的能力 聚类影响体细胞 LTCC 定位和功能、Ca2+ 诱导的 Ca2+ 释放或火花以及 LTCC 依赖性转录因子激活。拟议的研究有可能改变我们的 了解神经元离子通道如何调节以及这如何影响健康和疾病中的 Ca2+ 信号传导 当疾病改变时。