Ubiquitin-Dependent Endocytosis of Signaling Receptors

信号受体的泛素依赖性内吞作用

• 批准号: 6680278
• 负责人: Linda A. Hicke
• 金额: $ 26.14万
• 依托单位: NORTHWESTERN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-04-08 至 2007-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6680278
• 关键词: Saccharomyces cerevisiae; binding proteins; biological signal transduction; cell free system; cell membrane; genetic techniques; immunofluorescence technique; membrane proteins; phosphorylation; potassium channel; proteasome; protein kinase; protein protein interaction; receptor expression; receptor mediated endocytosis; ubiquitin; vesicle /vacuole

DESCRIPTION (provided by applicant): Monoubiquitination is a regulatory signal, like phosphorylation, that can alter the activity, location or structure of a protein. One function of monoubiquitin is to serve as a sorting signal in the endocytic pathway to promote the downregulation of activated signaling receptors and other plasma membrane proteins. Ubiquitin triggers the entry of endocytic cargo into primary endocytic vesicles budding from the plasma membrane. Ubiquitin is also a signal for the entry of receptors into vesicles that bud into the lumen of a late endosomal compartment, an event that is required for the delivery and degradation of receptors into the interior of the lysosome. Monoubiquitin plays multiple roles in regulating endocytic traffic. In addition to serving as a cargo sorting signal, monoubiquitin regulates the activity of the trans-acting endocytic machinery. Ubiquitin controls the cell surface activity of proteins involved in growth and differentiation, cell adhesion, hypertension, cardiac disease and neurotransmission. Ubiquitin-dependent endocytosis is also a mechanism that has been co-opted by viruses to downregulate host cell immune response proteins as part of the viral strategy to avoid immune surveillance. Furthermore, enveloped viruses, such as HIV and Ebola, appear to use the host cell ubiquitin-dependent endocytic machinery to assemble and bud from the plasma membrane. The mechanisms by which monoubiquitin bestows its regulatory activities have not been defined. In particular, ubiquitin-binding proteins that recognize and transmit the regulatory information conferred by monoubiquitination remain largely uncharacterized. To define the roles of ubiquitin signals in endocytosis and to provide paradigms for how monoubiquitin signals function in general, we will use biochemistry and genetics in Saccharomyces cerevisiae to characterize ubiquitin-binding endocytic proteins. We will 1) test models for the function of ubiquitin-binding proteins in the internalization and endosomal sorting machinery, 2) define the relationship between monoubiquitin-binding and intramolecular monoubiquitination for the CUEUb and UIM ubiquitin-binding domains; 3) identify ubiquitinated interacting partners of monoubiquitin-binding domains and 4) identify and characterize new ubiquitin-binding proteins that interact with the ubiquitin internalization signal.

描述（由申请人提供）：单泛素化是一种调节信号，例如磷酸化，可以改变蛋白质的活性，位置或结构。单喹素的一个功能是作为内吞途径中的分类信号，以促进活化信号受体和其他质膜蛋白的下调。泛素会触发内吞货物进入质膜的原代内吞囊泡。泛素也是将受体进入囊泡进入后期内体室腔的信号，这是将受体传递和降解进入溶酶体内部所需的事件。单喹素在调节内吞交通中起多种作用。除了用作货物排序信号外，单喹素还调节反式内吞机械的活性。 泛素控制参与生长和分化，细胞粘附，高血压，心脏病和神经传递的蛋白质的细胞表面活性。泛素依赖性内吞作用也是一种机制，该机制已被病毒选择，以下调宿主细胞免疫反应蛋白，作为避免免疫监测的病毒策略的一部分。此外，诸如HIV和埃博拉病毒之类的包膜病毒似乎使用宿主细胞依赖蛋白依赖性的内吞机械从质膜组装和芽。 尚未定义单纤维蛋白赋予其监管活动的机制。特别是，识别和传输单次夸夸其谈的调节信息的泛素结合蛋白在很大程度上没有表征。为了定义泛素信号在内吞作用中的作用，并为单纤维蛋白信号的一般起作用提供范例，我们将在酿酒酵母中使用生物化学和遗传学来表征泛素结合的蛋白质。 我们将1）测试模型，用于内在化和内体分类机制中泛素结合蛋白的功能，2）定义单纤维蛋白结合与cueub和UIM UIM泛素结合域的单纤维蛋白结合与分子内单次函数之间的关系； 3）确定单纤维素结合域的泛素化相互作用伴侣，4）识别和表征与泛素内在化信号相互作用的新的泛素结合蛋白。