Mechanism of degradation of the proteasome through autophagy

通过自噬降解蛋白酶体的机制

• 批准号: 9265475
• 负责人: Jeroen Roelofs
• 金额: $ 30万
• 依托单位: KANSAS STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-01 至 2021-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9265475
• 关键词: Active Sites; Aging; Alpha Cell; Animal Model; Autophagocytosis; Autophagosome; Biochemical; Biological; Biological Assay; Biological Process; Bortezomib; Cell Cycle Regulation; Cell Nucleus; Cell physiology; Cells; Complex; Cytosol; Data; Dependence; Deubiquitinating Enzyme; Dissociation; Ensure; Enzymes; Eukaryota; Eukaryotic Cell; Excision; FDA approved; Future; Genetic Screening; Genetic Transcription; Goals; Half-Life; Health; Human; Hydrolase; Knowledge; Lead; Link; Lysosomes; Malignant Neoplasms; Mammalian Cell; Mantle Cell Lymphoma; Membrane; Modification; Molecular; Multiple Myeloma; Neurodegenerative Disorders; Nitrogen; Nuclear; Nuclear Export; Nucleosome Core Particle; Nutrient; Organelles; Outcome; Oxidative Stress; Pathway interactions; Peptide Hydrolases; Pharmaceutical Preparations; Physiological; Plants; Play; Post-Translational Protein Processing; Process; Proteasome Inhibitor; Proteins; Quality Control; Regulation; Research; Role; Shapes; Signal Pathway; Signal Transduction; Signal Transduction Pathway; Starvation; Stress; System; Techniques; Testing; Therapeutic; Time; Transcriptional Regulation; Ubiquitin; Vacuole; Yeasts; base; cancer cell; fitness; fluorescence microscope; human disease; improved; insight; multicatalytic endopeptidase complex; particle; polypeptide; protein aggregate; public health relevance; receptor; response; screening; yeast genetics

 DESCRIPTION (provided by applicant): Two cellular components, the lysosome (vacuole in yeast and plants) and the proteasome degrade the majority of proteins in eukaryotic cells. They display a partial overlap in substrates and crosstalk between them has been observed. Therefore, to understand the cells ability to degrade proteins it is important to know how the cellular level of the proteasome is controlled. While transcriptional regulation of proteasomes has been studied in yeast and mammalian cells, little is known concerning the mechanism or physiological conditions that target proteasomes for degradation. Reducing proteasome levels through degradation can impact many cellular processes and increase a cell's sensitivity to drugs. This can be therapeutically relevant, because cells can become more sensitive to proteasome inhibitors, like the FDA approved drugs Bortezomib and Carfizomib used in the treatment of multiple myelomas and mantle cell lymphomas. The objective of the research proposed here is to elucidate at the molecular level the signal pathways and biological processes that lead to the degradation of proteasomes by using biochemical and cell biological assays. Since many proteasome related processes are highly conserved amongst eukaryotes and little is known about this process, yeast will be used as a model organism. This will provide a wider array of techniques and screening abilities to determine the basic mechanism involved. Based on our preliminary data, two distinct processes are proposed to lead to proteasome degradation. Aim 1 will determine how overall proteasome levels are reduced upon nitrogen starvation. The goal is to identify proteins, post- translational modifications, and other signals involved in the process of nuclear export and autophagic packaging upon nitrogen starvation. Aim 2 will test the hypothesis that proteasomes that fail quality control are specifically removed via autophagy. The goal is to determine how factors that recognize faulty proteasomes link these complexes to the autophagy pathway that targets them for lysosomal degradation. The expected outcomes from these aims are the identification and a molecular understanding of the process that leads to targeting of proteasomes for autophagy. Understanding of these pathways will be important for future characterization of the impact these processes have on conditions that are relevant for human health. This can include conditions like nutrient starved cancer cells, increased oxidative stress, aging, or neurodegenerative diseases, which all have been shown to be impacted by the ubiquitin- proteasome system.

 描述（由申请人提供）：两种细胞成分，溶酶体（酵母和植物中的液泡）和蛋白酶体降解真核细胞中的大多数蛋白质。它们在基板中表现出部分重叠，并且已观察到它们之间的串扰。因此，为了了解细胞降解蛋白质的能力，了解如何控制蛋白酶体的细胞水平非常重要。虽然已经在酵母和哺乳动物细胞中研究了蛋白酶体的转录调控，但对于靶向蛋白酶体降解的机制或生理条件知之甚少。通过降解降低蛋白酶体水平可以影响许多细胞过程并增加细胞对药物的敏感性。这可能与治疗相关，因为细胞可能对蛋白酶体抑制剂变得更加敏感，例如 FDA 批准的用于治疗多发性骨髓瘤和套细胞淋巴瘤的药物硼替佐米和卡非佐米。这里提出的研究的目的是通过使用生化和细胞生物学测定在分子水平上阐明导致蛋白酶体降解的信号途径和生物过程。由于许多蛋白酶体相关过程在真核生物中高度保守，并且人们对该过程知之甚少，因此酵母将被用作模型生物。这将提供更广泛的技术和筛选能力来确定所涉及的基本机制。根据我们的初步数据，提出了两种不同的过程来导致蛋白酶体降解。目标 1 将确定氮饥饿时总体蛋白酶体水平如何降低。目标是识别蛋白质、翻译后修饰以及氮饥饿时核输出和自噬包装过程中涉及的其他信号。目标 2 将检验以下假设：未通过质量控制的蛋白酶体会通过自噬被特异性去除。目标是确定识别有缺陷的蛋白酶体的因子如何将这些复合物与针对它们进行溶酶体降解的自噬途径联系起来。 这些目标的预期结果是对导致蛋白酶体靶向自噬的过程进行识别和分子理解。了解这些途径对于未来表征这些过程对人类健康相关条件的影响非常重要。这可能包括癌细胞营养匮乏等情况， 氧化应激增加、衰老或神经退行性疾病，所有这些都已被证明受到泛素-蛋白酶体系统的影响。