The Role of Ubiquitin Phosphorylation in Cellular Aging

泛素磷酸化在细胞衰老中的作用

• 批准号: 9165414
• 负责人: Jason A MacGurn
• 金额: $ 22.13万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2018-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9165414
• 关键词: Address; Adopted; Affect; Aging; Amino Acids; Amyotrophic Lateral Sclerosis; Biochemical; Cell Aging; Cell physiology; Cells; Critical Pathways; Data; Decision Making; Degradation Pathway; Development; Exhibits; Foundations; Functional disorder; Genetic; Genetic Screening; Goals; Homeostasis; Human; Huntington Disease; In Vitro; Lead; Longevity; Mediating; Membrane Protein Traffic; Metabolism; Mitotic; Nerve Degeneration; Neurodegenerative Disorders; Pathway interactions; Peptides; Phenotype; Phosphorylation; Phosphotransferases; Play; Positioning Attribute; Post-Translational Protein Processing; Proteins; Proteome; Proteomics; Reagent; Regulation; Research; Role; Serine; Signal Pathway; Signal Transduction; System; Testing; Therapeutic; Time; Ubiquitin; Ubiquitination; Work; Yeasts; cell age; genetic analysis; improved; multicatalytic endopeptidase complex; novel; protein degradation; protein misfolding; research study; screening; tool

Project Summary One of the cellular hallmarks of aging and neurodegeneration is a general decline in the protein degradation capacity of the cell, resulting in the accumulation of damaged and misfolded proteins which can threaten cellular integrity and viability. A key player in most cellular degradation pathways is ubiquitin – a 76 amino acid peptide that is covalently conjugated to proteins in order to target their degradation. Despite its central role in global protein stability we know very little about the regulation of ubiquitin itself. Thus, there is a critical need to understand the basic biochemical mechanisms responsible for regulating ubiquitin metabolism and to explore the relationship between ubiquitin homeostasis and cellular aging. Recently, we identified a novel signaling mechanism in yeast which regulates ubiquitin metabolism in the cell by controlling the phosphorylation of ubiquitin itself. Importantly, we have found that yeast cells expressing phosphomimetic ubiquitin exhibit a significantly extended post-mitotic lifespan. Given our preliminary results, we hypothesize that phosphorylation of ubiquitin not only alters its metabolism but generally accelerates global protein degradation and in doing so extends the post-mitotic life span of the cell. The experiments outlined in this proposal will explore this hypothesis in the following specific aims: Aim 1. Determine how ubiquitin phosphorylation extends yeast life span. We hypothesize that the life span extension associated with ubiquitin phosphorylation is due to a global increase in protein degradation. To test this, we will perform genetic analysis to define the degradation pathway that confers life span extension in the presence of phospho-ubiquitin. We will also leverage newly-developed reagents to define and quantify how ubiquitin phosphorylation affects the ubiquitin-modified proteome and how such changes may finely tune the activity of the ubiquitin-proteasome system during an aging time course. These experiments will elucidate the biochemical mechanism of life span extension associated with ubiquitin phosphorylation. Aim 2. Identify ubiquitin kinases and test their ability to modulate yeast aging. We hypothesize that the kinase activity responsible for Ser57 phosphorylation of ubiquitin will also play an important role in yeast chronological aging. To identify yeast ubiquitin kinase(s), we will adopt both genetic and biochemical screening approaches. Candidate kinases will be tested for membrane trafficking and cellular aging phenotypes. Identification of the yeast ubiquitin kinase(s) will significantly advance our understanding of ubiquitin metabolism and its relationship to the regulation of membrane traffic and post-mitotic aging. Together, the experiments outlined in this proposal have a strong potential to define the relationship between ubiquitin homeostasis, global protein stability, and cellular aging. Ultimately, this will contribute to our understanding of longevity in post-mitotic cells and may lead to the identification of new pathways that generally alter global protein stability.

项目概要 衰老和神经退行性变的细胞标志之一是蛋白质的普遍下降 细胞的降解能力，导致受损和错误折叠蛋白质的积累， 大多数细胞降解途径中的关键角色是泛素 – a 76。 与蛋白质共价结合的氨基酸肽，以靶向其降解。 泛素在整体蛋白质稳定性中的核心作用我们对泛素本身的调节知之甚少。 迫切需要了解负责调节泛素代谢的基本生化机制 为了探索泛素稳态与细胞衰老之间的关系，我们最近发现了一个。 酵母中的新信号传导机制，通过控制细胞中的泛素代谢来调节 重要的是，我们发现酵母细胞表达磷酸化模拟物。 鉴于我们的初步结果，泛素表现出显着延长的有丝分裂后寿命。 泛素的磷酸化不仅改变其新陈代谢，而且通常会加速整体蛋白质 降解并以此延长细胞有丝分裂后的寿命。 提案将在以下具体目标中探讨这一假设： 目标 1. 确定泛素磷酸化如何延长酵母寿命。 与泛素磷酸化相关的跨度扩展是由于蛋白质降解的整体增加。 对此进行测试，我们将进行遗传分析，以确定延长寿命的降解途径 我们还将利用新开发的试剂来定义和量化磷酸泛素的存在。 泛素磷酸化如何影响泛素修饰的蛋白质组以及这些变化如何进行微调 这些实验将阐明衰老过程中泛素蛋白酶体系统的活性。 与泛素磷酸化相关的寿命延长的生化机制。 目标 2. 鉴定泛素激酶并测试其调节酵母衰老的能力。 负责泛素 Ser57 磷酸化的激酶活性也将在酵母中发挥重要作用 为了识别酵母泛素激酶，我们将采用遗传和生物化学方法。 将测试候选激酶的膜运输和细胞老化。 表型的鉴定将显着增进我们对酵母泛素激酶的理解。 泛素代谢及其与膜交通调节和有丝分裂后衰老的关系。 总之，该提案中概述的实验具有定义这种关系的强大潜力 最终，这将有助于我们的泛素稳态、整体蛋白质稳定性和细胞衰老。 了解有丝分裂后细胞的寿命，并可能导致识别新的途径 通常会改变整体蛋白质的稳定性。