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、离子通道和黏附分子的精确数量和排列。这些蛋白在突触后膜上的定位或水平的变化调节突触功能，从而加强或削弱大脑中的突触连接。在所有真核细胞中，不同类型的膜蛋白的去除是通过网状蛋白介导的内吞作用进行的。尽管以前的研究已经帮助确定了非神经元细胞和突触前神经末梢的内吞机制，但笼蛋白介导的内吞作用在突触后间隔中的位置和调节及其在突触信号中的功能仍不清楚。 为了解决这些重要的问题，我的实验室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-哺乳动物大脑中主要的突触后间隔。我们最近发现，树突棘包含一个与突触后密度相邻但空间上分离的网状蛋白组装和内吞作用区域。这种内吞带形成并持续很长一段时间，不依赖于突触的活动，并用于集中运往内化的货物。利用这些初步数据以及我们监测和操纵神经元中笼状蛋白组装和货物摄取的能力，我们建议定义形成、维持和调节脊柱内细胞区的潜在分子和细胞机制，并确定脊柱成熟和突触传递的功能后果。这项工作将为突触形成和突触可塑性的基本机制提供洞察力。此外，由于笼蛋白介导的内吞作用调节神经元对与许多神经和精神疾病相关的广泛的病理侮辱和治疗剂的反应性，这些研究为开发新的治疗策略提供了希望。

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.