Kv2.1 membrane corrals:Regulators of K+ channel function and trafficking

Kv2.1 膜畜栏：K 通道功能和运输的调节者

• 批准号: 7994170
• 负责人: Michael M. TAMKUN
• 金额: $ 29.54万
• 依托单位: COLORADO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-12-01 至 2012-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7994170
• 关键词: Actins; Address; Apoptosis; Apoptotic; Attention; Axon; Binding; Biological Assay; Botulinum Toxins; Brain; Brain Hypoxia-Ischemia; Carbachol; Cardiovascular system; Cell physiology; Cell surface; Cells; Chemicals; Clathrin; Cystic Fibrosis; Cytoplasm; Cytoskeleton; DNA Sequence Rearrangement; Data; Defect; Detection; Diffuse; Diffusion; Disease; Electrodes; Electrophysiology (science); Endocrine system; Endocytosis; Epilepsy; Event; F-Actin; Glutamates; Health; Hippocampus (Brain); Human; Hyperactive behavior; Image; Injury; Ion Channel; Ion Channel Protein; Ischemia; Kv2.1 channel; Label; Life; Link; Location; Long QT Syndrome; Membrane; Mental Depression; Modeling; Modification; Molecular; Monitor; Movement; Mus; Mutagenesis; Neurobiology; Neuronal Injury; Neurons; Pathway interactions; Peptides; Permeability; Play; Potassium Channel; Protein Isoforms; Protein Kinase; Proteins; Publishing; Quantum Dots; Regulation; Research; Retrieval; Role; SNAP receptor; Signaling Molecule; Site; Site-Directed Mutagenesis; Stimulus; Stroke; Structure; Surface; Testing; Time; base; cell growth regulation; cellular imaging; density; human disease; improved; in vivo; inhibitor/antagonist; interdisciplinary approach; moesin; neuronal cell body; neuronal excitability; neurotransmitter release; programs; research study; response; response to injury; trafficking; voltage clamp; Actins; Address; Apoptosis; Apoptotic; Attention; Axon; Binding; Biological Assay; Botulinum Toxins; Brain; Brain Hypoxia-Ischemia; Carbachol; Cardiovascular system; Cell physiology; Cell surface; Cells; Chemicals; Clathrin; Cystic Fibrosis; Cytoplasm; Cytoskeleton; DNA Sequence Rearrangement; Data; Defect; Detection; Diffuse; Diffusion; Disease; Electrodes; Electrophysiology (science); Endocrine system; Endocytosis; Epilepsy; Event; F-Actin; Glutamates; Health; Hippocampus (Brain); Human; Hyperactive behavior; Image; Injury; Ion Channel; Ion Channel Protein; Ischemia; Kv2.1 channel; Label; Life; Link; Location; Long QT Syndrome; Membrane; Mental Depression; Modeling; Modification; Molecular; Monitor; Movement; Mus; Mutagenesis; Neurobiology; Neuronal Injury; Neurons; Pathway interactions; Peptides; Permeability; Play; Potassium Channel; Protein Isoforms; Protein Kinase; Proteins; Publishing; Quantum Dots; Regulation; Research; Retrieval; Role; SNAP receptor; Signaling Molecule; Site; Site-Directed Mutagenesis; Stimulus; Stroke; Structure; Surface; Testing; Time; base; cell growth regulation; cellular imaging; density; human disease; improved; in vivo; inhibitor/antagonist; interdisciplinary approach; moesin; neuronal cell body; neuronal excitability; neurotransmitter release; programs; research study; response; response to injury; trafficking; voltage clamp

DESCRIPTION (provided by applicant): Tremendous advances in ion channel research have been made with respect to channel structure and function. However, there is a lack of information regarding how living cells process ion channel proteins in real time. Such information is important since rapid modulation of ion channel surface expression is likely to represent a central mechanism in the regulation of cellular electrical excitability. Human diseases have already been linked to ion channel localization and trafficking defects. The Kv2.1 delayed-rectifier K+ channel targets to unique cell surface clusters in hippocampal neurons. Since these structures are regulated in vivo by stimuli associated with neuronal injury, i.e. hypoxia, ischemia, and excess neurotransmitter release, these microdomains are likely to participate in the neuro-protective response during such insults. However, Kv2.1 also plays a role in apoptosis, with this Kv isoform providing the increased K+ permeability required for the completion of the apoptotic program in cortical neurons. These diverse functions mandate that Kv2.1 activity and trafficking be tightly regulated. Our overall hypothesis is that the Kv2.1 surface clusters are central in the regulation of both Kv2.1 trafficking and function. Thus, a better understanding of cluster function will improve our ability to manage stroke-related issues. By clustering these channels within a defined surface compartment that serves as a platform for both insertion and retrieval, the regulation of trafficking is more efficient than if the channel is homogenously distributed over the cell surface. In addition, our preliminary data suggest that channels within the surface clusters do not conduct K+ until released from these cell surface domains, suggesting that K+ current density is controlled by more than transport to the cell surface. The proposed research will employ a multidisciplinary approach utilizing live cell imaging, single channel detection/tracking, site-directed mutagenesis and electrophysiology. The three Specific Aims will test the hypotheses that 1) Kv2.1 clusters represent cell surface platforms for channel insertion and retrieval, 2) stimulus-induced modification of the cortical cytoskeleton causes immediate release from the cell surface cluster and 3) Kv2.1 surface clusters are cell surface storage sites containing non-conducting channel. This research will have implications far beyond neurobiology, for Kv2.1 is the most widely expressed Kv channel and is also physiologically important to the cardiovascular and endocrine systems. PUBLIC HEALTH RELEVANCE: The proposed research examines the localization of the Kv2.1 potassium channel in brain neurons. This localization is essential in the neuro-protective response to stroke injury and hyperactivity in the brain. Mice lacking the Kv2.1 channel are epileptic and hyper-excitable. Understanding the molecular mechanisms underlying Kv2.1 localization will enhance the treatment of stroke and epilepsy.

描述（由申请人提供）：在通道结构和功能方面，离子通道研究的巨大进步。但是，缺乏有关活细胞如何实时处理离子通道蛋白的信息。这样的信息很重要，因为离子通道表面表达的快速调节可能代表了调节细胞电兴奋性的中心机制。人类疾病已经与离子通道定位和贩运缺陷有关。 Kv2.1延迟呈晶状体K+通道靶标在海马神经元中的独特细胞表面簇。由于这些结构受到与神经元损伤相关的刺激（即缺氧，缺血和过量神经递质释放）的刺激，因此这些微域在此类侮辱期间可能会参与神经保护反应。但是，KV2.1在凋亡中也起着作用，该KV同工型提供了在皮质神经元中完成凋亡程序所需的K+渗透性增加。这些多样化的功能要求将KV2.1活动和贩运受到严格的监管。我们的总体假设是KV2.1表面簇在调节Kv2.1运输和功能方面都是核心。因此，对群集功能的更好理解将提高我们管理与中风相关问题的能力。通过将这些通道聚集在定义的表面室内，该隔室用作插入和检索的平台，运输的调节比均匀分布在细胞表面上的通道更有效。此外，我们的初步数据表明，直到从这些细胞表面域释放之前，表面簇内的通道才导致K+，这表明K+电流密度不仅受到传输到细胞表面的运输。拟议的研究将采用使用活细胞成像，单个通道检测/跟踪，定向诱变和电生理学的多学科方法。这三个特定目的将检验以下假设：1）kv2.1簇代表用于通道插入和检索的细胞表面平台，2）刺激诱导的皮质细胞骨架的修饰，导致细胞表面簇立即释放，3）kv2.1 kv2.1表面簇是包含非降压通道的细胞表面存储位点。这项研究的含义将远远超出神经生物学，因为KV2.1是表达最广泛的KV渠道，并且在生理上对心血管和内分泌系统也很重要。 公共卫生相关性：拟议的研究研究了脑神经元中KV2.1钾通道的定位。这种定位对于对大脑中风损伤和多动症的神经保护反应至关重要。缺乏KV2.1通道的小鼠是癫痫病和过度启动的小鼠。了解KV2.1定位的分子机制将增强中风和癫痫的处理。