Physiology of proteasomes in Haloferax volcanii

Haloferax volcanii 蛋白酶体的生理学

基本信息

批准号：
6922534
负责人：
JULIE A MAUPIN-FURLOW
金额：
$ 21.46万
依托单位：
UNIVERSITY OF FLORIDA
依托单位国家：
美国
项目类别：
财政年份：
2000
资助国家：
美国
起止时间：
2000-04-01 至 2009-03-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by the applicant): Proteasomes are central to the quality control and regulated turnover of proteins and, thus, are major players in a variety of diseases which impact human health. The haloarchaeon Haloferax volcanii provides an excellent model system for understanding how these multisubunit complexes function as subtypes in the recognition and degradation of proteins in the absence of ubiquitin. This application is based on the identification of proteasome substrates by fluorescent reporter protein analysis and by differential proteomics of proteasome mutant and wild type strains. It is also based on the subunit topology of proteasome subtypes including 20S proteasomes of different alpha subunit composition and hetero- and homo-oligomeric forms of proteasome-activating nucleotidase AAA proteins. Furthermore, it is based on the growth-dependent differential regulation of the mRNA and protein levels of the subunits of these proteasomal subtypes as cells transition from log to stationary phase. This application will test the following hypotheses: (a) Subtypes of AAA ATPases recognize overlapping as well as unique sets of substrates for proteasome-mediated degradation, (b) 20S core particle subtypes of different alpha subunit composition differ in their affinity for these AAA ATPase subtypes, (c) The levels and post-translational modification of the AAA ATPases and alpha proteins are regulated to influence the timing and specificity of protein turnover. Thus, various combinations of AAA ATPase and 20S proteasome subtypes are proposed to form a network for the regulated turnover of proteins in the cell. The proposed combination of genetic and biochemical analysis will identify proteasomal substrates, define how proteasomal subtypes mediate recognition of these substrates, and elucidate the mechanisms involved in regulating the levels and posttranscriptional modification of the components of these proteasome subtypes in H. volcanii.

描述（由申请人提供）：蛋白酶体对于蛋白质的质量控制和调节周转至关重要，因此是影响人类健康的多种疾病的主要参与者。盐古菌 Haloferax volcanii 提供了一个优秀的模型系统，用于了解这些多亚基复合物如何在没有泛素的情况下作为蛋白质识别和降解的亚型发挥作用。该应用基于通过荧光报告蛋白分析以及蛋白酶体突变体和野生型菌株的差异蛋白质组学来鉴定蛋白酶体底物。它还基于蛋白酶体亚型的亚基拓扑，包括不同 α 亚基组成的 20S 蛋白酶体以及蛋白酶体激活核苷酸酶 AAA 蛋白的异源和同源寡聚形式。此外，它基于当细胞从对数期过渡到稳定期时，这些蛋白酶体亚型的亚基的 mRNA 和蛋白质水平的生长依赖性差异调节。该应用将测试以下假设：(a) AAA ATP酶的亚型识别蛋白酶体介导的降解的重叠底物以及独特的底物组，(b) 不同α亚基组成的20S核心颗粒亚型对这些AAA ATP酶的亲和力不同亚型，(c) AAA ATP 酶和 α 蛋白的水平和翻译后修饰受到调节，以影响蛋白质周转的时间和特异性。因此，提出了 AAA ATP 酶和 20S 蛋白酶体亚型的各种组合来形成细胞中蛋白质调节周转的网络。所提出的遗传和生化分析的结合将鉴定蛋白酶体底物，定义蛋白酶体亚型如何介导这些底物的识别，并阐明参与调节 H. volcanii 中这些蛋白酶体亚型成分的水平和转录后修饰的机制。