Trafficking and Proteolysis of Notch and Other Gamma-Secretase Substrates

Notch 和其他γ-分泌酶底物的运输和蛋白水解

基本信息

批准号：
8259436
负责人：
Mark E Fortini
金额：
$ 31.42万
依托单位：
THOMAS JEFFERSON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-05-01 至 2014-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8259436
关键词：
Affect Alzheimer&apos s Disease Amyloid Amyloid beta-Protein Precursor Aspartic Endopeptidases Biochemical Biogenesis Biological Biology Brain Cell Adhesion Molecules Cell physiology Cell surface Cells Chromosomes Cleaved cell Complex Data Development Disease Drosophila genus Early Endosome Endocytosis Endosomes Event Excision Family Genes Genetic Genetic Screening Goals Health Human Immune system Integral Membrane Protein Intracellular Membranes Ions Lead Ligand Binding Ligands Light Lysosomes Malignant Neoplasms Mammalian Cell Mediating Membrane Membrane Protein Traffic Molecular Molecular Cloning Mutation Neurodegenerative Disorders Neurons Pathogenesis Pathway interactions Peptides Play Process Production Proteins Proteolysis Proteolytic Processing Receptor Signaling Recovery Recycling Research Proposals Role Route Screening Result Signal Pathway Signal Transduction Sorting - Cell Movement T-Cell Leukemia T-Lymphocyte Water amyloid precursor protein processing animal tissue brain tissue cell fate specification gamma secretase human disease human tissue interest member mutant notch protein novel secretase solute trafficking tumorigenesis water channel

项目摘要

DESCRIPTION (provided by applicant): Many integral membrane proteins have been identified as cleavage substrates for the intramembrane aspartyl protease complex termed ??secretase. These ??secretase substrates include receptors for signaling pathways, adhesion molecules, and other factors that are localized at the cell surface and whose activities are regulated by ??secretase-mediated cleavage. Understanding the molecular details of ??secretase substrate biology is important due to the prominent role that many substrates play in normal cellular physiology and in human disease. For example, the Notch receptor, a well- characterized ??secretase substrate, is essential for proper cell-fate specification and cellular differentiation during the development of animal and human tissues. Inappropriate activation of the Notch pathway in the human immune system causes T-cell leukemia and dysregulated Notch activity has been implicated in other cancers and developmental diseases. Furthermore, processing of the Amyloid Precursor Protein (APP) by ??secretase contributes directly to the production of secreted amyloid-2 peptide in human brain tissue, a crucial event in the pathogenesis of Alzheimer's disease. A key feature of ??secretase substrate cleavage is its tight control by ligand binding, ectodomain removal, and other regulatory processes. A growing body of data indicates that cleavage also depends upon intracellular membrane trafficking of ??secretase substrates and their sorting within specific trafficking compartments. In the case of both Notch and APP, ??secretase-mediated cleavage is associated with endocytosis of the substrate from the cell surface and its entry into endosomes. We have found that proper biogenesis of the early endosome compartment requires the function of an aquaporin channel protein, defining a specialized endosome route for efficient ??secretase-dependent Notch trafficking and signaling. In Specific Aim 1, we propose to characterize further the role of this aquaporin in endosome biogenesis and Notch trafficking. These studies will shed light on the cell biological aspects of ?? secretase substrate trafficking and their relationship to ??secretase substrate cleavage, recycling, and degradation. In Specific Aim 2, we propose to conduct a forward genetic screen for new factors involved in the intracellular membrane trafficking of Notch and other ??secretase substrates. Preliminary results from this screen have already proven to be very promising, including the recovery of many potentially new genes needed for various steps of Notch intracellular trafficking. Further analysis and molecular cloning of several of these new genes is now underway. The main goal of this project is to advance our understanding of ??secretase substrate trafficking and its relevance to secretase- dependent processes in tumorigenesis and neurodegenerative disease. PUBLIC HEALTH RELEVANCE: Proteins cleaved by ??secretase, including the Notch receptor and amyloid precursor protein, are important for developmental signaling and neuronal function, and their dysregulation contributes to cancer and neurodegenerative disease. This research proposal seeks to identify cellular factors that control the production, trafficking, and proteolytic processing of ?? secretase targets. These studies might lead to the identification of new proteins and intracellular pathways that could be therapeutically targeted in cancer and neurodegenerative disorders.

描述（由申请人提供）：许多积分膜蛋白已被鉴定为被称为泌尿酶的膜内膜内膜蛋白酶复合物的裂解底物。这些??泌液酶底物包括信号通路，粘附分子和其他位于细胞表面的因素且活性受到泌尿酶介导的裂解调节的受体。由于许多底物在正常的细胞生理和人类疾病中所起的重要作用，因此了解泌尿酶底物生物学的分子细节很重要。例如，在动物和人体组织的发展过程中，Notch受体是一种良好的表征？泌尿酶底物。人类免疫系统中缺口途径的不当激活导致T细胞白血病和失调的Notch活性与其他癌症和发育疾病有关。此外，神蛋白酶对淀粉样蛋白前体蛋白（APP）的加工直接促进了人脑组织中分泌的淀粉样蛋白-2肽的产生，这是阿尔茨海默氏病发病机理的关键事件。？泌尿酶底物裂解的一个关键特征是其通过配体结合，外神经群的去除和其他调节过程的严格控制。越来越多的数据表明，裂解还取决于泌液酶底物的细胞内膜运输及其在特定贩运室内的分类。在Notch和App的情况下，泌尿酶介导的裂解与底物的内吞作用相关，并从细胞表面及其进入内体。我们发现，早期内体室的适当生物发生需要水通道通道蛋白的功能，从而定义了一种专门的内体途径，以进行有效的secressement依赖性凹槽运输和信号传导。在特定的目标1中，我们建议进一步表征这种水通道蛋白在内体生物发生和缺口贩运中的作用。这些研究将阐明？分泌酶底物贩运及其与泌尿酶底物的裂解，回收和退化的关系。在特定的目标2中，我们建议对Notch和其他??泌液酶底物的细胞内膜运输的新因素进行前遗传筛选。该屏幕的初步结果已经被证明是非常有希望的，包括恢复了Notch细胞内贩运所需的许多潜在的新基因。现在正在进行一些新基因的进一步分析和分子克隆。该项目的主要目标是提高我们对肿瘤发生和神经退行性疾病中泌尿酶依赖性过程的介绍酶底物运输的理解。公共卫生相关性：由泌尿酶裂解的蛋白质，包括Notch受体和淀粉样蛋白前体蛋白，对于发育信号传导和神经元功能很重要，它们的失调有助于癌症和神经退行性疾病。该研究建议旨在确定控制生产，贩运和蛋白水解处理的细胞因素？分泌酶靶标。这些研究可能导致鉴定新蛋白质和细胞内途径，这些蛋白质可能针对癌症和神经退行性疾病。