Probing the Structure of the Synapse Using Superresolution Light Microscopy

记忆和其他认知功能部分取决于神经元之间突触连接的模式和强度。了解突触强度的分子决定因素一直是神经科学的长期目标，这一领域的进展将影响我们对从自闭症到阿尔茨海默病的几乎所有神经系统疾病的理解。的疾病。在过去的十年中，生物化学和传统的分子和遗传学方法已经开始拼凑神经递质受体和其他突触蛋白之间的相互作用如何调节和控制突触强度和可塑性，但一个主要的限制是，很少或根本没有关于蛋白质如何在突触上排列成信号复合物的结构信息。许多信号分子只能与紧邻的蛋白质相互作用，这种定位本身可能受到经验的调节。了解功能性信号复合物是如何产生的，以及它们又是如何调节突触强度的，因此需要我们探测突触后密度（PSD）内蛋白质的空间排列。常规方法不具有足够的分辨率以允许在这些微小（< 1 μ m）突触结构内映射突触蛋白的位置。在这里，我建议开发工具来映射PSD内单个突触蛋白（如谷氨酸受体）的空间排列，并确定这些空间排列如何受到突触可塑性的影响，使用超分辨率光学显微镜。通过映射突触后膜和PSD内许多不同蛋白质的相对位置，我们将能够生成包含突触后侧的蛋白质晶格的三维模型。这种方法有希望把大量的生物化学和分子数据的蛋白质-蛋白质相互作用的结构背景下，这是必不可少的解释，并将增加一个强大的新工具，突触功能的分析。

Memory and other cognitive functions reside in part in the pattern and strength of synaptic connections between neurons. Understanding the molecular determinants of synaptic strength has been a longstanding goal of neuroscience, and advances in this field stand to influence our understanding of virtually every neurological disorder from Autism to Alzheimer?s disease. Over the past decade biochemical and conventional molecular and genetic approaches have begun to piece together how interactions between neurotransmitter receptors and other synaptic proteins regulate and control synaptic strength and plasticity, but a major limitation is that there is little or no structural information about how proteins are arranged into signaling complexes at the synapse. Many signaling molecules can only interact with immediately adjacent proteins, and this localization may itself be regulated by experience. Understanding how functional signaling complexes are generated and how they in turn regulate synaptic strength thus requires that we probe the spatial arrangements of proteins within the postsynaptic density (PSD). Conventional approaches do not have sufficient resolution to allow the position of synaptic proteins to be mapped within these tiny (< 1 im) synaptic structures. Here I propose to develop tools to map the spatial arrangements of individual synaptic proteins (such as glutamate receptors) within the PSD, and to determine how these spatial arrangements are influenced by synaptic plasticity, using super resolution light microscopy. By mapping the relative positions of many different proteins within the postsynaptic membrane and PSD we will be able to generate a 3 dimensional model of the protein lattices that comprise the postsynaptic side of the synapse. This method has the promise to put a vast array of biochemical and molecular data on protein-protein interactions into a structural context that is essential for its interpretation, and will add a powerful new tool to the analysis of synaptic function.