The Arsenic Stress Signaling Code of Yeast

酵母的砷应激信号编码

• 批准号: 10224278
• 负责人: DAVID E. LEVIN
• 金额: $ 43.89万
• 依托单位: BOSTON UNIVERSITY MEDICAL CAMPUS
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-08-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10224278
• 关键词: Air; Arsenates; Arsenic; Arsenicals; Arsenites; Binding; Biochemical; Cardiovascular Diseases; Cell membrane; Cell surface; Cells; Cellular Metabolic Process; Chronic; Code; Cysteine; Diabetes Mellitus; Disease; Environment; Enzymes; Event; Evolution; Exposure to; Food; Food Contamination; Genetic; Glycerol; Health; Hypertension; Iron; Lead; MAP Kinase Gene; MEKKs; MEKs; Malignant Neoplasms; Mammals; Metabolic; Metabolic Biotransformation; Metabolism; Modeling; Modification; Molecular; Nature; Osmolar Concentration; Osmotic Shocks; Output; Oxidative Regulation; Oxidative Stress; Pathway interactions; Post-Translational Protein Processing; Production; Protein Kinase; Protein Tyrosine Phosphatase; Protein phosphatase; Proteins; Reactive Oxygen Species; Regulation; Replication Initiation; Role; Route; Signal Transduction; Signaling Molecule; Source; Specificity; Stress; Substrate Specificity; Sulfhydryl Compounds; Testing; Toxic effect; Toxin; Tyrosine; Water; Yeasts; anthropogenesis; aqueous; base; behavior influence; biological adaptation to stress; cancer therapy; cancer type; carcinogenicity; cell behavior; chemotherapeutic agent; effective therapy; exposed human population; geochemistry; ground water; inorganic phosphate; interest; nervous system disorder; novel; novel strategies; protein activation; protein function; response; stress activated protein kinase; stressor

Project Summary Arsenic is the most prevalent toxin in the environment. This natural metalloid enters the biosphere from geochemical sources and, to a lesser degree, from anthropogenic sources. Human exposure to arsenic is mainly through food, water and air, and contamination of groundwater poses a worldwide health problem. Inorganic aqueous arsenic exists mainly as oxyanions of trivalent arsenite [As(III)] and pentavalent arsenate [As(V)]. As(V) is much less toxic than As(III), which is thiol reactive and binds covalently to cysteine residues in proteins. Chronic exposure to inorganic arsenic is associated with cardiovascular disease and hypertension, diabetes mellitus, neurological disorders, and various forms of cancer. It has been proposed that both direct modification of biomolecules by As(III) and reactive oxygen species (ROS) generated by arsenicals are responsible for its toxicity and carcinogenicity. Despite these health effects, As(III) is used as a highly effective treatment for certain types of cancers. Therefore, it is important to understand the cellular responses mobilized by arsenic-induced stress. Both As(V) and As(III) exposure stimulate the yeast stress-activated MAPK (SAPK) Hog1, whose activity is critically important for the cellular response to arsenic. We are interested in two general questions. First, how do diverse stressors activate a small number of SAPKs? We have found that many stressors activate yeast SAPKs by intracellular routes that interface with SAPK pathways in atypical ways, rather than signaling from the cell surface, which may influence the behavior of the SAPK. Second, how does the cell mobilize coherent, stress-specific outputs from an activated SAPK? This proposal centers on the cellular responses to arsenic exposure. We have developed evidence that both As(III) and its methylated metabolite, MAs(III), are important signaling molecules that allow cells to mobilize protective, stress-specific responses through modification of specific cysteine residues in target proteins. We refer to this as an arsenic stress signaling code. Aim1 extends our recent findings that cells respond differently to As(V) and As(III) exposure. We propose to understand the mechanistic bases of distinct regulatory events driven by these stressors. We will identify key targets of arsenic modification for the regulation of the glycerol channel Fps1 [the major port of entry for As(III)], and test the role of newly discovered arsenic modifications of proteins involved in the regulation of the oxidative stress response and replication initiation. Aim 2 is to understand how Hog1 activated by As(III) drives stress-specific outputs. This aim extends our recent finding that Hog1 itself is modified by arsenic and that this modification is important for its role in the response to As(III). Using mass spectral approaches, we will determine the Hog1 phosphorylome in response to As(III) and As(V) and establish whether Hog1 target specificity is altered by arsenylation. Aim 3 is to delineate the novel pathway by which As(V) activates Hog1 and to determine its significance for As(V) entry to cells. Completion of these aims will establish a novel paradigm centered on the regulatory nature of protein arsenylation.

项目摘要 砷是环境中最普遍的毒素。这种天然的类金属物质从 来自地球化学源，在较小程度上，来自人为来源。人类对砷的暴露是 主要通过食物、水和空气，地下水的污染构成了一个世界性的健康问题。 无机水砷主要以三价亚砷酸盐[As(III)]和五价砷酸盐的含氧阴离子形式存在 [AS(V)]。As(V)的毒性比As(III)小得多，As(III)是硫醇活性的，与半胱氨酸残基共价结合 蛋白质。长期接触无机砷与心血管疾病和高血压有关， 糖尿病、神经疾病和各种形式的癌症。有人建议，这两个直接 砷化合物产生的As(III)和ROS对生物分子的修饰 对其毒性和致癌性负责。尽管有这些健康影响，砷(III)被用作一种高效的 治疗某些类型的癌症。因此，了解动员的细胞反应是很重要的。 通过砷诱导的压力。As(V)和As(III)暴露均可刺激酵母应激激活的MAPK(SAPK) Hog1，其活性对于细胞对砷的反应至关重要。我们对两位将军感兴趣 问题。首先，不同的压力源是如何激活少数SAPKs的？我们发现有很多 应激源通过细胞内途径激活酵母SAPKs，这些途径以非典型的方式与SAPK途径对接， 而不是来自细胞表面的信号，这可能会影响SAPK的行为。第二，如何 细胞从激活的SAPK中动员连贯的、应激特异性的输出？这项提案的中心是 细胞对砷暴露的反应。我们发现了As(III)及其甲基化的证据 代谢产物Mas(III)是重要的信号分子，允许细胞动员保护性的、应激特异性的 通过修饰靶蛋白中特定的半胱氨酸残基来响应。我们把这种物质称为砷 压力信号代码。Aim1扩展了我们最近的发现，即细胞对As(V)和As(III)的反应不同 曝光。我们建议理解由这些因素驱动的不同监管事件的机制基础 压力源。我们将确定砷修饰的关键靶点，以调节甘油通道Fps1 [As(III)的主要入境口岸]，并测试新发现的砷对蛋白质的修饰作用 参与氧化应激反应和复制启动的调节。目标2是了解如何 AS(III)激活的Hog1驱动特定压力的输出。这一目标扩展了我们最近的发现，即Hog1本身是 有一种观点认为，这种修饰是用砷修饰的，而且这种修饰对于它在应对砷(III)的反应中的作用是重要的。使用体量 光谱方法，我们将测定Hog1磷酸组对As(III)和As(V)的响应并建立 砷基化是否改变了Hog1靶标的特异性。目标3是描绘一条新的途径，通过它 As(V)激活Hog1，并确定其对As(V)进入细胞的意义。完成这些目标将 建立一个以蛋白质砷基化的调节性质为中心的新范式。