Role of Molecular Chaperones in Stress Response and Disease

分子伴侣在应激反应和疾病中的作用

• 批准号: 9925819
• 负责人: Ursula H. Jakob
• 金额: $ 64.62万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-05-01 至 2022-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9925819
• 关键词: Acids; Amyloid; Amyloidosis; Bacteria; Biochemical; Blood; Cells; Disease; Dissociation; Enterobacteriaceae; Eukaryota; Exposure to; Goals; Host Defense; Hypochlorous Acid; Insecta; Leishmania infantum; Mammals; Microbial Biofilms; Mitochondria; Molecular Chaperones; Molecular Conformation; Mutation; Neurodegenerative Disorders; Neurons; Organism; Oxidation-Reduction; Parasites; Parkinson Disease; Pathway interactions; Physiological; Play; Polymers; Polyphosphates; Polyps; Process; Proteins; Research; Resistance; Resolution; Role; Site; Stomach; Stress; Structure; Suggestion; System; Temperature; Testing; Time; Toxic effect; Work; Yeasts; acid stress; amyloid formation; analog; antimicrobial; beta pleated sheet; biological adaptation to stress; disulfide bond; flexibility; improved; novel; pathogenic bacteria; protein folding; protein protein interaction; proteotoxicity; scaffold; thermostability; tool

Many organisms regularly encounter fast-acting, highly proteotoxic stress conditions, including exposure to the physiological antimicrobial hypochlorous acid (HOCl), highly elevated temperatures or acid stress. To survive these stress conditions, they employ a class of ATP-independent, stress specific chaperones, whose posttranslational activation is tailored towards the stress conditions that require their chaperone functions. Our lab investigates four of these stress-specific chaperones; Hsp33, which is activated by oxidative disulfide bond formation to protect bacteria and eukaryotic parasites against HOCl, which is commonly produced by cells of the innate host defense; Get3, a redox-regulated Hsp33 analogue that protects yeast and likely other eukaryotes against oxidative protein damage; HdeA, which is rapidly activated by acid-induced dissociation and protects enteric bacteria against acid-stress encountered in the mammalian stomach; and mitochondrial Prdx2 from Leishmania infantum, which is a temperature-regulated chaperone that protects parasites against the sudden temperature shift as they transit from insects to warm-blooded mammals. All four of these proteins are chaperone-inactive and stably folded under non-stress conditions but are activated following very rapid, stress-induced conformational rearrangements, converting them into proteins with extensive regions of intrinsic disorder. We will now combine mutational, biochemical and high-resolution structural tools to elucidate the precise working mechanism of these proteins, testing the hypothesis that stress-induced unfolding serves to generate novel, highly flexible protein-protein interaction sites. These studies have the potential to open up a completely new perspective in chaperone research, protein folding and stress response pathways. In a separate line of research, we discovered that polyphosphate (polyP), which is a universally conserved, very abundant and ubiquitously distributed polymer, works as a highly effective protein-stabilizing scaffold. This demonstrates that protein chaperones are not the only cellular solution to deal with proteotoxic stress conditions. We found that polyP increases the thermostability of proteins by stabilizing them in a predominantly β-sheet conformation. This finding helps to explain how polyP confers resistance to stress conditions that cause protein unfolding. At the same time, it also explains how polyP acts to accelerate processes such as bacterial biofilm formation, which depend on the stabilization of amyloid-like proteins in a fibril-forming cross-β-sheet conformation. We recently realized that polyP equally accelerates fibril formation of disease-associated amyloids. This activity appears to reduce the amount of toxic oligomers and, most importantly, protects neurons against amyloid toxicity. We will now further investigate this exciting suggestion that polyP is a physiologically important cytoprotective modifier of amyloidogenic processes, and might play a role in Parkinson's disease and potentially other neurodegenerative diseases associated with amyloid formation.

许多生物体经常遇到快速作用、高蛋白毒性的应激条件，包括暴露于 生理抗菌次氯酸 (HOCl)、高温或酸胁迫下生存。 在这些应激条件下，它们采用一类不依赖于 ATP 的应激特异性伴侣，其 翻译后激活是针对需要其伴侣功能的应激条件而定制的。 实验室研究了其中四种应激特异性伴侣；Hsp33 由氧化二硫键激活； 形成以保护细菌和真核寄生虫免受次氯酸的侵害，次氯酸通常由以下细胞产生 先天宿主防御；Get3，一种氧化还原调节的 Hsp33 类似物，可保护酵母和其他可能的物质 真核生物抵抗氧化蛋白损伤；HdeA 被酸诱导的解离迅速激活； 保护肠道细菌免受哺乳动物胃和线粒体中的酸应激； 来自婴儿利什曼原虫的 Prdx2，它是一种温度调节伴侣，可保护寄生虫免受侵害 当它们从昆虫转变为温血哺乳动物时温度突然变化 所有这四种蛋白质。 分子伴侣在非应激条件下不活跃且稳定折叠，但在非常快的速度后被激活， 应激诱导的构象重排，将其转化为具有广泛内在区域的蛋白质 我们现在将结合突变、生化和高分辨率结构工具来阐明这一疾病。 这些蛋白质的精确工作机制，检验压力诱导的展开有助于的假设 这些研究有可能开辟新的、高度灵活的蛋白质-蛋白质相互作用位点。 伴侣研究、蛋白质折叠和应激反应途径的全新视角。 在单独的研究中，我们发现聚磷酸盐 (polyP)，这是一种普遍保守的、非常 丰富且分布广泛的聚合物，可作为高效的蛋白质稳定支架。 证明蛋白质伴侣并不是应对蛋白毒性应激的唯一细胞解决方案 我们发现，polyP 通过稳定蛋白质来提高蛋白质的热稳定性。 主要是β-片层构象，这一发现有助于解释polyP如何赋予抗应激能力。 同时，它还解释了polyP如何加速蛋白质的展开。 细菌生物膜形成等过程取决于淀粉样蛋白在细菌中的稳定性 我们最近意识到，polyP 同样可以加速原纤维的形成。 这种活性似乎可以减少有毒低聚物的量，并且大多数。 重要的是，保护神经元免受淀粉样蛋白毒性。我们现在将进一步研究这一令人兴奋的建议。 PolyP 是淀粉样蛋白生成过程的生理上重要的细胞保护调节剂，并且可能发挥 在帕金森病和与淀粉样蛋白相关的其他潜在神经退行性疾病中的作用 形成。