Regulation of Actin Dynamics at Functional Subdomains within Dendritic Spines

树突棘功能子域肌动蛋白动力学的调节

• 批准号: 8115116
• 负责人: Nicholas Alonzo Frost
• 金额: $ 4.03万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8115116
• 关键词: Actins; Behavioral; Binding; Biological Assay; Brain; Cells; Chemicals; Chemosensitization; Confocal Microscopy; Cytoskeletal Modeling; Cytoskeleton; DNA Sequence Rearrangement; Dendritic Spines; Disease; Endocytosis; Excitatory Synapse; Filament; Functional disorder; Head; Housing; Impairment; Individual; Interphase Cell; Label; Learning; Life; Long-Term Potentiation; Maintenance; Measures; Mediating; Membrane; Microfilaments; Microscopy; Modification; Molecular; Molecular Machines; Motion; Movement; Neurons; Neurotransmitter Receptor; Pattern; Plastics; Positioning Attribute; Process; Proteins; Regulation; Relative (related person); Resolution; SH3 Domains; Site; Synapses; Synaptic plasticity; Techniques; Testing; Vertebral column; density; developmental plasticity; human EMS1 protein; light microscopy; nervous system disorder; particle; polymerization; postsynaptic; research study; single molecule

DESCRIPTION (provided by applicant): Dendritic spines house the postsynaptic components of excitatory synapses in the brain. Synapses are inherently plastic, and dendritic spines represent an important locus for maintenance and modification of synaptic strength which is thought to underlie behavioral learning and developmental plasticity. Increasing evidence exists that spines contain within them interlinked sets of functional subdomains. Most notable of these is the postsynaptic density, the molecular machine which positions and regulates the number of postsynaptic neurotransmitter receptors. In addition, spines contain an endocytic zone positioned in the spine membrane substantially away from the synapse. The synaptic dysfunction underlying many neurological disorders is associated with impairment of processes occurring at these functional subdomains. Importantly, a number of these processes require ongoing actin polymerization. Dynamic regulation of the actin cytoskeleton within spines is necessary for spine morphological plasticity as well as maintenance of synaptic composition and function, and underlies the insertion, stabilization, and endocytosis of neurotransmitter receptors at the synapse. Changes in actin polymerization and stability within spines accompany and are required for the induction of long term potentiation and other forms of synaptic plasticity. However, little is known about the sites within spines at which actin rearrangement is specifically required for alterations in synaptic strength to be initiated and maintained. I propose that ongoing and independent regulation of actin polymerization occurs at spine subdomains such as the postsynaptic density and endocytic zone. My proposed experiments will test this hypothesis by measuring actin polymerization and movement within individual, live dendritic spines using confocal, super-resolution, and single-particle techniques, and utilizing fluorescent protein-tagged molecules to mark the postsynaptic density (PSD) and endocytic zones. Using these assays, I will then test a widely proposed mechanism that the PSD interacts with the actin cytoskeleton via the protein cortactin, and examine how the organization of actin is altered within spines during induction of LTP. These results will provide fundamental new information about cytoskeletal organization and regulation within individual dendritic spines, critical for understanding the involvement of spine actin dysregulation in disease.

描述（由申请人提供）：树突棘容纳大脑中兴奋性突触的突触后成分。突触本质上是可塑的，树突棘是维持和修改突触强度的重要场所，被认为是行为学习和发育可塑性的基础。越来越多的证据表明，脊柱中含有相互关联的功能子域集。其中最值得注意的是突触后密度，它是定位和调节突触后神经递质受体数量的分子机器。此外，棘包含位于棘膜中的内吞区，该内吞区基本上远离突触。许多神经系统疾病背后的突触功能障碍与这些功能子域发生的过程损伤有关。重要的是，其中许多过程需要持续的肌动蛋白聚合。棘内肌动蛋白细胞骨架的动态调节对于棘形态可塑性以及突触组成和功能的维持是必要的，并且是突触处神经递质受体的插入、稳定和内吞作用的基础。棘内肌动蛋白聚合和稳定性的变化伴随并是诱导长期增强和其他形式的突触可塑性所必需的。然而，人们对棘内哪些位点知之甚少，在这些位点上，肌动蛋白重排对于启动和维持突触强度的改变是特别需要的。我认为肌动蛋白聚合的持续且独立的调节发生在脊柱亚域，例如突触后密度和内吞区。我提出的实验将通过使用共焦、超分辨率和单粒子技术测量个体活树突棘内的肌动蛋白聚合和运动，并利用荧光蛋白标记分子来标记突触后密度（PSD）和内吞区来检验这一假设。 。然后，我将使用这些测定来测试一种广泛提出的机制，即 PSD 通过蛋白质皮质蛋白与肌动蛋白细胞骨架相互作用，并检查在诱导 LTP 期间肌动蛋白在棘内的组织如何改变。这些结果将提供有关个体树突棘内细胞骨架组织和调节的基本新信息，对于理解脊柱肌动蛋白失调在疾病中的参与至关重要。