The Role of the Proteasome in Aging

描述(由申请人提供)：由于其在细胞内蛋白质周转中的已知作用，泛素-蛋白酶体途径有望在细胞衰老中发挥关键作用。蛋白酶体是一种多功能、多亚基的蛋白水解酶，是该途径中的一个焦点，负责控制对短寿命代谢调节蛋白和损伤长寿命蛋白的切割。调节作用和“垃圾清除”功能都可能在与年龄相关的代谢减慢和疾病中发挥作用。然而，有关蛋白酶体与衰老的关系的研究一直是有限的、不确定的，有时甚至是相互矛盾的。我建议以一种真正全面的方式表征衰老小鼠肝组织中的蛋白酶体组装：分别在不同的亚细胞隔间中，并考虑活性、特异性、组装状态和亚单位组成。新出现的证据表明，蛋白酶体根据亚细胞位置执行特定的职责，这证明了我的方法是正确的。我假设有一组与年龄相关的变化，这些变化共同形成了一种特征模式，构成了衰老的标志。我希望将这种特征称为蛋白酶体老化指数。我的初步数据支持这样一个观点，即这样的指数是可以披露的。具体地说，我建议：(1)在蛋白酶体亚细胞定位的每个年龄组中定义蛋白酶体老化指数。我将对蛋白酶体的以下性质进行分子图谱分析：蛋白酶体亚组分的含量和组成，亚组分中选定的亚基的蛋白质含量，以及所有三个活性部位的肽酶活性，用模型底物确定。(2)将蛋白酶体指数与天然底物的裂解模式相关联。(3)最后，我将使用蛋白酶体老化指数来建立氧化应激小鼠模型中蛋白酶体途径的状态：以氧化应激增加为特征的SOD1-/-小鼠和接受热量限制的小鼠作为氧化应激降低的模型。蛋白酶体衰老指数的成功推出将成为一个新的平台，以探索蛋白酶体及其分子背景中与年龄相关的变化，了解变化的生理后果，并提出纠正这些变化的方法。蛋白酶体是一种多功能酶，负责控制大多数细胞蛋白质的降解，已被认为与年龄相关的蛋白质周转率下降有关。我计划在蛋白酶体中定义一种与年龄相关的变化模式：“衰老的蛋白酶体指数”。这样的指数将有助于检测细胞衰老的迹象，并有助于建立旨在控制衰老过程的治疗方法。

DESCRIPTION (provided by applicant): Due to its known role in protein turnover in the cell, the ubiquitin-proteasome pathway is expected to be a key player in cellular aging. The proteasome, a multifunctional, multisubunit proteolytic enzyme, is a focal point in the pathway and is in charge of controlled cleavage of short-lived metabolic regulator proteins and damaged long-lived proteins. Both the regulatory role and the "garbage removal" function may have a role in age-related metabolic slowdown and diseases. However, studies implicating the proteasome in aging have been limited, inconclusive, and at times contradictory. I propose to characterize proteasomal assemblies in aging mice liver tissue in a truly comprehensive manner: separately in distinct subcellular compartments, and taking into account activity, specificity, assembly status, and subunit composition. The emerging evidence that proteasomes perform specific duties based on subcellular location justifies my approach. I hypothesize that there is a set of age-related alternations, which collectively form a characteristic pattern of properties that constitutes a signature of aging. I wish to call such signature the proteasome aging index. My preliminary data support the notion that such index can be revealed. Specifically, I propose to: (1) define the proteasome aging index in each age group specific for subcellular localization of proteasomes. I will perform molecular profiling of the following properties of proteasome: content and composition of proteasome subassemblies, protein content of selected subunits of the subassemblies and peptidase activities of all three active sites, determined with model substrates. (2) I will correlate the proteasome index with the pattern of cleavage of natural substrates. (3) Finally, I will employ the proteasome aging index to establish the state of the proteasome pathway in the oxidative stress mice models: the SOD1-/- mice characterized by an increased oxidative stress and mice subjected to caloric restriction accepted as a model of decreased oxidative stress. Successful launching of the proteasome aging index will serve as a novel platform to pursue age-related alterations in the proteasome and its molecular context, learning about physiological consequences of the changes, and propose the means to correct them. The proteasome, a multifunctional enzyme responsible for controlled degradation of most of cellular proteins, has been linked to an age-related decline in protein turnover. I plan to define a pattern of age-related changes in the proteasome: the "proteasome index of aging". Such an index will help to detect signs of cellular aging and help to establish treatments aiming at controlling the aging processes.