Role of Glutaredoxin in Metabolic Oxidative Stress

谷氧还蛋白在代谢氧化应激中的作用

• 批准号: 6733292
• 负责人: YONG J LEE
• 金额: $ 24.39万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-02-05 至 2008-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6733292
• 关键词: JUN kinase; biochemistry; biological signal transduction; cysteine; free radical oxygen; glucose; glutathione; high performance liquid chromatography; mitogen activated protein kinase; molecular genetics; neoplastic cell; oxidative stress; oxidoreductase; prostate neoplasms; protein structure function; site directed mutagenesis; thioredoxin; tissue /cell culture

DESCRIPTION (provided by applicant): The long-term goal of the proposed research project is to understand the molecular mechanisms of cellular responses to the unique tumor microenvironment (low glucose concentration, chronic hypoxia, and low extracellular pH). We previously observed that glucose deprivation increases the intracellular concentration of hydroperoxide. It also activates the SAPK (stress activated protein kinase) signal transduction pathway. In this grant proposal, we postulate that glutaredoxin (GRX), a redox-regulatory protein, recognizes the metabolic oxidative stress and triggers the ASK1-MEK-MAPK signal transduction pathway. The guiding hypothesis is that glucose deprivation raises the intracellular level of reactive oxygen species (ROSs) and increases the level of oxidized glutathione. GRX, which contains two redox-active half-cystine residues (Cys-Pro-Tyr-Cys) in an active center, recognizes metabolic oxidative stress through catalysis of thiol-disulfide interchange reactions with oxidized molecules such as oxidized glutathione. The oxidized GRX dissociates from ASK1 (apoptosis signal regulating kinase 1). The dissociation of GRX from ASK1 results in the activation of ASK1 and subsequently activates the ASK1-MEK-MAPK signal transduction pathway. The specific aims of this project are to examine (1) how GRX recognizes the metabolic oxidative stress, (2) the role of GRX in the ASK1-MEK-MAPK signal transduction pathway, (3) cooperation between GRX and thioredoxin (TRX) to regulate ASKI activation during glucose deprivation. The proposed studies for the first aim employ site-directed mutagenesis to create a point mutant at the redox-active site as well as at other cysteine residues. These studies will illustrate how half-cystine residues are involved in the recognition of metabolic oxidative stress. The second aim will employ molecular genetics and biochemical techniques to elucidate the involvement of GRX in the ASK1-MEK-MAPK signal transduction pathway. The third aim will use the immune complex kinase assay to assess the effect of intracellular glutathione deprivation, extracellular oxidized glutathione treatment, inhibition of GRX or TRX gene expression on ASK1 activation. We believe that investigating the mechanisms of metabolic oxidative stress responses in tumor cells will provide insight into how tumor cells recognize metabolic oxidative stress and initiate signal transduction.

描述（由申请人提供）：拟议研究项目的长期目标是了解细胞对独特肿瘤微环境（低葡萄糖浓度、慢性缺氧和低细胞外pH值）反应的分子机制。我们以前观察到，葡萄糖剥夺增加细胞内氢过氧化物的浓度。它还激活SAPK（应激激活蛋白激酶）信号转导途径。本研究假设谷氧还蛋白（GRX）是一种氧化还原调节蛋白，它识别代谢性氧化应激并触发ASK 1-MEK-MAPK信号转导通路。指导性假设是葡萄糖剥夺提高了细胞内活性氧（ROS）的水平，并增加了氧化型谷胱甘肽的水平。GRX在活性中心含有两个具有氧化还原活性的半胱氨酸残基（Cys-Pro-Tyr-Cys），其通过催化与氧化分子如氧化型谷胱甘肽的硫醇-二硫键交换反应来识别代谢氧化应激。氧化的GRX从ASK 1（凋亡信号调节激酶1）解离。GRX与ASK 1的解离导致ASK 1的激活，并随后激活ASK 1-MEK-MAPK信号转导通路。本课题的具体目的是研究（1）GRX如何识别代谢性氧化应激;（2）GRX在ASK 1-MEK-MAPK信号转导通路中的作用;（3）GRX与硫氧还蛋白（TRX）在葡萄糖剥夺过程中对ASKI活化的协同调节作用。第一个目标的拟议研究采用定点诱变，在氧化还原活性位点以及其他半胱氨酸残基处产生点突变体。这些研究将说明半胱氨酸残基是如何参与代谢氧化应激的识别。第二个目标是利用分子遗传学和生物化学技术来阐明GRX参与ASK 1-MEK-MAPK信号转导途径。第三个目标将使用免疫复合物激酶测定来评估细胞内谷胱甘肽剥夺、细胞外氧化型谷胱甘肽处理、GRX或TRX基因表达抑制对ASK 1活化的影响。我们相信，研究肿瘤细胞中代谢氧化应激反应的机制将为了解肿瘤细胞如何识别代谢氧化应激并启动信号转导提供帮助。