The Endocytic Machinery of Dendritic Spines

描述（由申请人提供）： 神经传递需要突触上受体、离子通道和粘附分子的精确数量和排列。这些蛋白质在突触后膜的定位或水平的改变调节突触功能，从而加强或削弱大脑中的突触连接。在所有真核细胞中，通过网格蛋白介导的内吞作用去除不同类型的膜蛋白。虽然以前的研究已经帮助定义了内吞机制在非神经元细胞和突触前神经末梢，网格蛋白介导的内吞作用的位置和调节突触后隔室及其功能的作用，突触信号仍然未知。 为了解决这些重要的问题，我的实验室已经启动了一个生化和细胞生物学研究计划，以分析树突棘的内吞机制-哺乳动物大脑中的主要突触后区室。我们最近发现，树突棘包含一个区域的网格蛋白组装和内吞相邻，但空间隔离，突触后密度。这种内吞区的形成和持续很长一段时间独立于突触活动，并用于集中货物注定内化。利用这些初步的数据和我们的能力，监测和操纵网格蛋白组装和货物摄取神经元中，我们建议定义潜在的分子和细胞机制，形成，维持和调节内吞区的脊柱，并确定脊柱成熟和突触传递的功能后果。这项工作将提供深入了解突触形成和突触可塑性的基本机制。此外，由于网格蛋白介导的内吞作用调节神经元对广泛的病理性损伤和与许多神经和精神疾病相关的治疗剂的反应，这些研究有望开发新的治疗策略。

DESCRIPTION (provided by applicant): Neurotransmission requires a precise number and arrangement of receptors, ion channels, and adhesion molecules at synapses. Alterations in the localization or levels of these proteins at the postsynaptic membrane regulates synapse function, thereby strengthening or weakening synaptic connections in the brain. In all eukaryotic cells, removal of membrane proteins of diverse types occurs by clathrin-mediated endocytosis. Although previous studies have helped define the endocytic machinery in nonneuronal cells and the presynaptic nerve terminal, the location and regulation of clathrin-mediated endocytosis within postsynaptic compartments and its functional role in synaptic signaling remain unknown. To address these important questions, my laboratory has initiated a program of biochemical and cell biological studies to analyze the endocytic machinery of dendritic spines - the primary postsynaptic compartment in the mammalian brain. We have recently found that dendritic spines contain a zone of clathrin assembly and endocytosis adjacent to, but spatially segregated from, the postsynaptic density. This endocytic zone forms and persists over long periods of time independent of synaptic activity, and serves to concentrate cargo destined for internalization. Taking advantage of these preliminary data and our ability to monitor and manipulate clathrin assembly and cargo uptake in neurons, we propose to define the underlying molecular and cellular mechanisms that form, maintain and regulate the endocytic zone of spines, and determine the functional consequences for spine maturation and synaptic transmission. This work will provide insight into fundamental mechanisms that underlie synapse formation and synaptic plasticity. Moreover, because clathrin-mediated endocytosis regulates neuronal responsiveness to a wide range of pathologic insults and therapeutic agents relevant to numerous neurologic and psychiatric diseases, these studies hold promise for the development of novel therapeutic strategies.