Supramolecular Organization of the Postsynaptic Density

突触是神经元交流的基础。CA1领域最清楚地证明了这一点 啮齿动物的海马体，突触的功效可以随着时间的推移而变化。这种突触调节是许多方面的基础 更高级的大脑功能。它的功能障碍与发育障碍和某些类型的 癫痫，并可能是多种神经精神疾病的重要因素。现在普遍认为 位于突触后密度(PSD)内的蛋白质在调节突触效能方面起着关键作用，但 这些蛋白质在PSD中的组织在很大程度上仍不清楚。阐明超分子 PSD的架构是该项目的长期目标。 目前的证据表明，每个NMDA受体都与许多信号、适配器和 细胞骨架蛋白形成单独的半自主信号“模块”，但这些现在已被理解 只是作为生物化学的抽象。拟议的研究将免疫金EM与高分辨率相结合 电子断层扫描研究NMDAR模块作为一个有组织的物理结构，确定其大小 和塑造，并审视其内部组织。它还探讨了这些模块的组织方式 PSD内更大的结构域，并研究PSD与细胞骨架的关系。特定目标 1确定NMDAR信号模块的形态；特定目标2阐明内部 NMDAR模块的组织，使用免疫金标记法表征 一个模块中的四个主要蛋白质；特定目标3检查NMDAR模块沿 突触并置；以及特定目标4研究PSD和肌动蛋白细胞骨架之间的联系， 以及脊椎内肌动蛋白细丝的组织。 这项研究计划解决了突触分子信号通路的物理组织 在海马区，重点研究与一种特别重要的神经递质类型相关的蛋白质 受体，NMDA受体。这项工作的成功完成将提高我们对突触的理解 大脑机制，将提供新的线索，关于基础学习和 记忆，并可能有助于理解各种神经性、发育和精神性疾病的原因 精神错乱。

Synapses are fundamental to neuronal communication. As most clearly demonstrated in the CA1 field of rodent hippocampus, synaptic efficacy can vary over time. This synaptic modulation underlies many aspects of higher brain function. Its dysfunction is implicated in developmental disorders and certain types of epilepsy, and may be important for a variety of neuropsychiatric diseases. It is now generally agreed that proteins lying within the postsynaptic density (PSD) play a key role in regulating synaptic efficacy, but the organization of these proteins within the PSD remains largely unknown. Elucidating the supramolecular architecture of the PSD is the long-term goal of this project. Current evidence suggests that each NMDA receptor combines with numerous signaling, adaptor, and cytoskeletal proteins to form individual semi-autonomous signaling "modules," but these are now understood only as biochemical abstractions. The proposed research combines immunogold EM with high-resolution electron tomography to study the NMDAR module as an organized physical structure, determining its size and shape, and examining its internal organization. It also explores the organization of these modules into larger domains within the PSD, and investigates the relationship of the PSD to the cytoskeleton. Specific Aim 1 determines the morphology of NMDAR signaling modules; Specific Aim 2 elucidates the internal organization of NMDAR modules, using immunogold mapping to characterize the laminar organization of four major proteins within a module; Specific Aim 3 examines the distribution of NMDAR modules along the synaptic apposition; and Specific Aim 4 investigates contacts between the PSD and the actin cytoskeleton, and the organization of actin filaments within the spine. This research proposal addresses the physical organization of molecular signaling pathways at synapses in the hippocampus, focusing on proteins associated with an especially important type of neurotransmitter receptor, the NMDA receptor. Successful completion of this work will improve our understanding of synaptic mechanisms in the brain, will provide new clues regarding fundamental processes that underlie learning and memory, and may help understand the causes of a variety of neurological, developmental, and psychiatric disorders.