STRUCTURAL CORRELATES OF PROTEASOME REGULATORS

蛋白酶体调节剂的结构相关性

• 批准号: 6180532
• 负责人: EDWARD Peter GOGOL
• 金额: $ 12.53万
• 依托单位: UNIVERSITY OF MISSOURI KANSAS CITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-05-01 至 2002-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6180532
• 关键词: binding sites; cryoelectron microscopy; electron microscopy; enzyme activity; enzyme mechanism; enzyme substrate complex; image enhancement; protease inhibitor; proteasome; protein binding; protein structure; proteolysis; stoichiometry; ubiquitin

DESCRIPTION (Adapted from applicant's abstract): The controlled degradation of most cellular proteins is performed by large protein complexes known as proteasomes that are found in both the nucleus and cytoplasm of an cells. Proteasome activity is central to almost all cell processes, including aspects of protein synthesis and turnover, cell cycle control, metabolic response to environment and immune response, and is implicated in a number of disease states, including cancer and Alzheimer's disease. While the catalytic mechanism of the proteolytic sites has been clarified by recent structural work, there is only a preliminary upstanding of the factors involved in regulation and targeting of proteasome activity. This proposal seeks to determine the interactions of the proteasome with three of the best-characterized regulators of its activity. The first of these is the major activator, PA700, which is responsible for targeting the proteasome to ubiquitinated substrates. Hydrolysis of this class of substrates is believed to be the single most important cellular role of the proteasome. Using electron of negatively stained specimens, we have shown that PA700 binds to the 20S proteasome and converts in to another previously-isolated form (26), in an apparently cooperative manner. Moreover, another protein complex that increases the activation of proteasome by PA700, called modulator, promotes the formation of the PA700 caps without itself forming any stable association with the resulting 26S proteasome. They now seek to correlate the observed structural modification with proteolytic activity, and to better define the organization of the multiple subunits and activities of the PA700 proteasome regulator, by extending our electron microscopy and image analysis studies to include cryo-electron microscopy and three-dimensional reconstructions. A second major component of this proposal is the structural examination of an alternative activator of the proteasome. PA28, which is responsible for the role of the proteasome in antigen presentation. They will define its structural organization, and determine its interaction with PA700 in mixed complexes. The third component of this proposal is a parallel study of the binding site and structural correlates of a specific protein inhibitor of the proteasome, P131, and its effects on formation of activated proteasomes.

描述（改编自申请人的摘要）：受控降解 大多数细胞蛋白质的作用是由大型蛋白质复合物执行的，称为 蛋白酶体存在于细胞的细胞核和细胞质中。 蛋白酶体活性是几乎所有细胞过程的核心，包括 蛋白质合成和周转、细胞周期控制、代谢等方面 对环境和免疫反应的反应，并涉及许多 疾病状态，包括癌症和阿尔茨海默病。 虽然 最近的研究已经阐明了蛋白水解位点的催化机制 结构工作，仅对因素进行初步了解 参与蛋白酶体活性的调节和靶向。 该提案旨在确定蛋白酶体的相互作用 拥有三个最具特色的监管机构。 第一个 其中主要激活剂 PA700 负责靶向 蛋白酶体到泛素化底物。 此类的水解 底物被认为是最重要的细胞作用 蛋白酶体。 使用负染色样本的电子，我们已经证明 PA700 与 20S 蛋白酶体结合并转化为另一种蛋白酶体 先前孤立的形式（26），以明显合作的方式。 此外，另一种蛋白质复合物可以增加 PA700 的蛋白酶体，称为调节剂，促进 PA700 的形成 帽本身不与所得的 26S 形成任何稳定的关联 蛋白酶体。 他们现在寻求将观察到的结构修饰关联起来 具有蛋白水解活性，并更好地定义蛋白质的组织 PA700 蛋白酶体调节剂的多个亚基和活性，通过 扩展我们的电子显微镜和图像分析研究，包括 冷冻电子显微镜和三维重建。 该提案的第二个主要组成部分是结构审查 蛋白酶体的替代激活剂。 PA28，负责 了解蛋白酶体在抗原呈递中的作用。 他们将定义 其结构组织，并确定其与 PA700 的相互作用 混合复合物。 该提案的第三个组成部分是对约束力的并行研究 特定蛋白质抑制剂的位点和结构相关性 蛋白酶体、P131 及其对活化蛋白酶体形成的影响。