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

基本信息

批准号：
7674704
负责人：
STEVEN G CLARKE
金额：
$ 18.3万
依托单位：
UNIVERSITY OF CALIFORNIA LOS ANGELES
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-08-15 至 2011-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7674704
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 Reaction Resistance Role Saccharomyces cerevisiae Signal Transduction Signal Transduction Pathway Staging Stress System Time Tissues Urine Work Yeasts ascorbate deprivation healthy aging interest link protein normal aging oxidation oxidative damage prevent protein metabolism racemization repair enzyme repaired response stem success

项目摘要

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）：衰老中人类功能丧失的很大一部分可能是由于受损蛋白质的积累。负责人体大多数催化和结构作战的蛋白质可以随时间自发分解。随着生物的年龄，蛋白质会积累足够的化学损伤，甚至有毒。衰老生物的成功可能取决于它们首先识别哪些蛋白质受损的能力，然后修复或去除这些物种。在此提案中，我们想了解生物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。我们对主要损害，蛋白质天冬氨酸和天冬酰基残基的主要损害，同性异构化和种族化是如何通过由L-异源石（D-撒胃）蛋白O-甲基转移酶enzyme和特定蛋白质含量的蛋白质蛋白质和特定的蛋白质蛋白质的蛋白质来最小化的。我们建议将小鼠，酵母（酿酒酵母）和线虫蠕虫（秀丽隐杆线虫）用作模型系统。这些系统中的每一个都有帮助我们破译人类也可以使用的途径。我们将首先检查小鼠蛋白质修复与蛋白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，在约60天大的时候，在维修不足的小鼠中损坏的天冬氨酸残基的积累。同时，小鼠尿液中受损的肽的水平增加，这表明一种去除未经修复蛋白的蛋白水解系统被激活。我们建议表征此备份系统，并在正常的老化过程中找到其作用。然后，我们将检查缺乏蛋白质修复甲基转移酶的酵母菌中含有受损的天冬氨酸残基的蛋白质的代谢。我们已经表明，尽管它们的形成与其他生物体相同，但含有含有损坏的天冬氨酸残基的蛋白质并未积聚在酵母中。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，并通过生化和遗传方法的结合来表征它们。最后，我们将比较小鼠的修复/蛋白水解反应与在衰老中发生的小鼠。我们实验室的先前工作表明，蛋白水解可能与线虫秀丽隐杆线虫中的蛋白质修复耦合。我们将表征缺乏L-异冬酰胺基甲基转移酶的蠕虫，重点是专门用于生存的蠕虫的两个幼虫阶段，在没有修复酶的情况下似乎受到最大的影响。蠕虫和小鼠的维修，信号传导和蛋白水解系统的相似性表明，我们在这里学到的知识对人类健康至关重要。 7.项目叙述我们想了解人类细胞如何进行分子修复和替换过程，从而有助于健康的衰老以及这些途径中的缺陷如何导致疾病。对于人体功能所必需的蛋白质分子被自发化学过程不断降解。除非修复或更换受损的分子，否则它们的积累会减慢或停止正常的生理功能。