Linked Protein Repair, Proteolysis, and Oxidation in Aging

衰老过程中的相关蛋白质修复、蛋白水解和氧化

• 批准号: 7509152
• 负责人: STEVEN G CLARKE
• 金额: $ 21.09万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-15 至 2010-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7509152
• 关键词: Affect; Age; Aging; Aging-Related Process; Animals; Antioxidants; Ascorbic Acid; Autophagocytosis; Back; Biochemical Genetics; Biological Models; Caenorhabditis elegans; Cells; Chemicals; Coupled; Defect; Disease; Enzymes; Galactose; Gene Proteins; Genes; Health; Homologous Gene; Human; Insulin; Knockout Mice; Laboratories; Lead; Learning; Link; Mammalian Cell; Maps; Mass Spectrum Analysis; Measures; Methyltransferase; Molecular; Mus; Muscle Form Glycogen Phosphorylase; Nature; Nematoda; Nutrient; Operative Surgical Procedures; Organism; Pathway interactions; Peptides; Phosphorylases; Physiological; Plants; Process; Protein O-Methyltransferase; Proteins; Proteolysis; Rate; Reaction; Resistance; Role; Saccharomyces cerevisiae; Signal Transduction; Signal Transduction Pathway; Staging; Stress; System; Time; Tissues; Urine; Work; Yeasts; ascorbate; day; deprivation; healthy aging; interest; link protein; normal aging; oxidation; prevent; protein metabolism; racemization; repair enzyme; repaired; response; stem; success

DESCRIPTION (provided by applicant): A significant part of the loss of human function in aging may be due to the build-up of damaged proteins. Proteins, responsible for most of the catalytic and structural operations of the body, can spontaneously break down with time. As organisms age, proteins can accumulate enough chemical damage to become inactivated, or even toxic. The success of aging organisms may depend upon their ability to first recognize which proteins are damaged, and then to either repair or remove these species. In this proposal, we want to understand how organisms integrate protein repair and proteolytic pathways to stem the accumulation of damaged proteins. We are particularly interested in how a major type of spontaneous damage, the isomerization and racemization of protein aspartyl and asparaginyl residues, is minimized by a combination of molecular repair initiated by the L-isoaspartyl-(D-aspartyl) protein O- methyltransferase enzyme and specific proteolytic degradation reactions. We propose to use mice, yeast (Saccharomyces cerevisiae), and nematode worms (Caenorhabditis elegans) as model systems. Each of these systems has advantages to aid us in deciphering the pathways that may also be used in humans. We will first examine the links between protein repair and proteolysis pathways in mice. We will focus on pathways used in animals lacking the protein repair methyltransferase. We have previously established that the accumulation of damaged aspartyl residues in repair deficient mice levels off after about 60 days of age. At the same time, the levels of damaged peptides in the urine of the mice increases, suggesting that a proteolytic system to remove the unrepaired proteins is activated. We propose to characterize this back-up system and to find its role in the normal aging process. We will then examine the metabolism of proteins containing damaged aspartyl residues in the yeast S. cerevisiae that lacks the protein repair methyltransferase. We have shown that proteins containing damaged aspartyl residues do not accumulate in yeast, although they appear to be formed at the same rate as in other organisms. We thus propose that yeast have specific proteolytic systems to prevent the accumulation of these altered proteins and will characterize them by a combination of biochemical and genetic approaches. Finally, we will compare the repair/proteolysis responses of mice to those that occur in aging worms. Previous work in our laboratory has suggested that proteolysis may be coupled to protein repair in the nematode C. elegans. We will characterize worms deficient in the L-isoaspartyl methyltransferase, focusing on two larval stages of worms that are specialized for survival and that appear to be most affected in the absence of the repair enzyme. Similarities in repair, signaling, and proteolysis systems in worms and mice suggest that what we learn here will be important for human health. 7. PROJECT NARRATIVE We want to understand how human cells can perform molecular repair and replacement processes that contribute to healthy aging and how defects in these pathways lead to disease. Protein molecules essential for body functions are continuously being degraded by spontaneous chemical processes. Unless damaged molecules are repaired or replaced, their accumulation can slow or stop normal physiological functions.

描述（由申请人提供）：衰老中人体功能丧失的重要部分可能是由于受损蛋白质的积累。蛋白质负责身体的大部分催化和结构操作，可以随着时间的推移自发分解。随着生物体的衰老，蛋白质会积累足够的化学损伤，使其失去活性，甚至有毒。衰老生物体的成功可能取决于它们首先识别哪些蛋白质受损，然后修复或去除这些物种的能力。在这项提案中，我们希望了解生物体如何整合蛋白质修复和蛋白水解途径，以阻止受损蛋白质的积累。我们特别感兴趣的是，一种主要类型的自发性损伤，异构化和外消旋化的蛋白质乙酰基和天冬酰胺基残基，是如何最小化的分子修复的L-异乙酰基-（D-乙酰基）蛋白质O-甲基转移酶和特定的蛋白水解降解反应启动的组合。我们建议使用小鼠，酵母（酿酒酵母），线虫（秀丽隐杆线虫）作为模型系统。这些系统中的每一个都有帮助我们破译可能也用于人类的途径的优势。我们将首先研究小鼠中蛋白质修复和蛋白质水解途径之间的联系。我们将专注于缺乏蛋白质修复甲基转移酶的动物中使用的途径。我们先前已经确定，在修复缺陷小鼠中受损的乙酰基残基的积累在约60日龄后趋于平稳。与此同时，小鼠尿液中受损肽的水平增加，表明蛋白水解系统被激活，以去除未修复的蛋白质。我们建议描述这个备份系统，并找到它在正常老化过程中的作用。然后，我们将研究在酵母S中含有受损的乙酰基残基的蛋白质的代谢。酿酒酵母缺乏蛋白质修复甲基转移酶。我们已经表明，含有受损的乙酰基残基的蛋白质不会在酵母中积累，尽管它们似乎以与其他生物相同的速率形成。因此，我们建议，酵母具有特定的蛋白水解系统，以防止这些改变的蛋白质的积累，并将其特征的生化和遗传方法的组合。最后，我们将比较小鼠的修复/蛋白水解反应与老化蠕虫中发生的反应。我们实验室以前的工作表明，在线虫C中，蛋白质水解可能与蛋白质修复偶联。优美的我们将描述蠕虫缺乏L-异戊酰甲基转移酶，专注于两个幼虫阶段的蠕虫，专门为生存，似乎是最受影响的修复酶的情况下。蠕虫和小鼠在修复、信号传导和蛋白质水解系统方面的相似之处表明，我们在这里学到的知识对人类健康很重要。7.我们希望了解人类细胞如何进行有助于健康衰老的分子修复和替换过程，以及这些途径的缺陷如何导致疾病。对身体功能至关重要的蛋白质分子不断被自发的化学过程降解。除非受损分子得到修复或替换，否则它们的积累会减缓或停止正常的生理功能。