Mechanisms of Endosome-to-Lysosome Trafficking in Brain

脑内内体到溶酶体的运输机制

• 批准号: 6986745
• 负责人: LIAN LI
• 金额: $ 27.64万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-12-01 至 2007-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6986745
• 关键词: Huntington' s disease; RNA interference; biochemistry; biological signal transduction; cell biology; confocal scanning microscopy; endocytosis; endopeptidases; epidermal growth factor; growth factor receptors; immunoelectron microscopy; immunoprecipitation; intracellular transport; laboratory mouse; laboratory rat; lysosomes; molecular biology; nerve /myelin protein; neural degeneration; phosphoproteins; protein localization; protein protein interaction; protein structure function; proteomics; tissue /cell culture; transport proteins; vesicle /vacuole

DESCRIPTION (provided by applicant): The endosomal-lysosomal pathway is a major proteolytic system in neurons as well as in other eukaryotic cells. The importance of this pathway in neuronal signaling and synaptic function is highlighted by recent findings that disturbed endosome-to-lysosome trafficking in Drosophila mutants results in abnormal synaptic growth and impaired neurotransmission. Furthermore, aberrations in this pathway have been implicated in the pathogenesis of a number of neurological disorders and neurodegenerative diseases, including Alzheimer's disease, Huntington's disease, and more than 40 lysosomal storage disorders. Despite the critical importance of the endosomal-lysosomal pathway in normal physiology and diseases, the molecular mechanism that controls endosome-to-lysosome trafficking remains poorly characterized. The long-term goal of this research is to understand, at the molecular level, how endocytosed proteins are sorted and transported to lysosomes for degradation, and how this process becomes dysregulated in neurological and neurodegenerative diseases. Recent work by the applicant and others has revealed a crucial role for the endosomal protein hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs) in regulating endosome-to-lysosome trafficking. However, the mechanism of action of Hrs remains unclear. The applicant's preliminary studies have identified three Hrs-interacting proteins, sorting nexin 1 (SNXl), signal transducing adaptor molecule (STAM), and huntingtin-associated protein 1 (HAP1). This project will test the hypothesis that Hrs and its associated proteins SNXl, STAM, and HAP1 are key components of the endosomal trafficking machinery that control the sorting and trafficking of endocytosed proteins to lysosomes for degradation. A combination of biochemical, proteomic, molecular biological, and cell biological approaches will be used to characterize Hrs-associated protein complexes and determine their roles in ubiquitin-dependent endosome-to-lysosome trafficking and in neurodegeneration. Results from these studies should generate novel insights into the molecular mechanism governing endosome-to-lysosome trafficking in neurons, and advance our understanding of the pathogenic mechanism of abnormal endosomal-lysosomal pathway in a variety of neurological disorders and neurodegenerative diseases.

描述（由申请人提供）：内体-溶酶体途径是神经元以及其他真核细胞中的主要蛋白水解系统。最近的研究结果强调了这一途径在神经元信号传导和突触功能中的重要性，即果蝇突变体中内体到溶酶体的运输受到干扰，导致突触生长异常和神经传递受损。此外，该途径中的畸变已经涉及许多神经障碍和神经变性疾病的发病机制，包括阿尔茨海默病、亨廷顿病和超过40种溶酶体贮积症。尽管内体-溶酶体途径在正常生理学和疾病中至关重要，但控制内体至溶酶体运输的分子机制仍缺乏表征。这项研究的长期目标是在分子水平上了解内吞蛋白如何被分类并转运到溶酶体进行降解，以及这一过程如何在神经系统和神经退行性疾病中失调。申请人和其他人最近的工作已经揭示了内体蛋白肝细胞生长因子调节的酪氨酸激酶底物（Hrs）在调节内体至溶酶体运输中的关键作用。然而，Hrs的作用机制仍不清楚。申请人的初步研究已经鉴定了三种Hrs相互作用蛋白，分选连接蛋白1（SNX 1）、信号转导衔接分子（STAM）和亨廷顿蛋白相关蛋白1（HAP 1）。该项目将测试Hrs及其相关蛋白SNX 1、STAM和HAP 1是内体运输机制的关键组分的假设，所述内体运输机制控制内吞蛋白的分选和运输到溶酶体以进行降解。生物化学，蛋白质组学，分子生物学和细胞生物学方法的组合将被用来表征Hrs相关蛋白复合物，并确定其在泛素依赖性内体到溶酶体运输和神经变性中的作用。这些研究结果将为神经元内体-溶酶体转运的分子机制提供新的见解，并促进我们对异常内体-溶酶体通路在各种神经系统疾病和神经退行性疾病中的致病机制的理解。