How Molecular Chaperones Promote Pathogen Survival During Starvation

分子伴侣如何促进饥饿期间病原体的存活

• 批准号: 10605789
• 负责人: Carissa Chan
• 金额: $ 4.77万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-11-28 至 2024-11-27
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10605789
• 关键词: Affinity; Anti-Bacterial Agents; Bacteria; Bacterial Drug Resistance; Bacterial Infections; Binding; Biochemical; Biological Process; Cell physiology; Cells; Cytoplasm; Dependence; Disease; Divalent Cations; Environment; Equilibrium; Face; Gene Expression; Genes; Growth; Guanosine Triphosphate; Health; Human; Immune; In Vitro; Infection; Life; Macrophage; Maintenance; Mediating; Microbe; Molecular; Molecular Chaperones; Nature; Nucleotides; Nutrient; Nutritional; Organism; Pathway interactions; Phenotype; Physiological; Process; Proliferating; Protein Biosynthesis; Proteins; Proteomics; Repression; Research; Resources; Ribosomes; Role; Salmonella typhimurium; Specific qualifier value; Starvation; Stress; System; Testing; Tissues; Translations; Virulence; Work; biological adaptation to stress; burden of illness; deprivation; examination questions; experience; falls; human pathogen; improved; in vivo; microbial; microorganism; novel; pathogen; pathogenic bacteria; pathogenic microbe; polypeptide; protein aggregation; protein folding; proteostasis; response; stem; tripolyphosphate

PROJECT SUMMARY All life forms synthesize and maintain proteins to carry out fundamental cell processes. Protein synthesis and maintenance require tremendous energy and resources, including Mg2+, the most abundant divalent cation in living cells. Microbial pathogens often face nutrient limitation inside mammalian macrophages and must restore protein homeostasis to persist in host tissues. I propose to determine how the facultative intracellular pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium) uses molecular chaperones to control protein homeostasis, thereby enabling survival during Mg2+ starvation. I discovered two novel functions for DnaK, the highly conserved molecular chaperone that functions with cochaperones in folding proteins under nutrient-replete conditions. First, I established that, surprisingly, DnaK represses protein synthesis by binding ribosomes in a cochaperone-independent manner when S. Typhimurium experiences low Mg2+, thereby helping conserve energy and resources. And second, I determined that DnaK antagonizes the canonical ribosome-associated chaperone Trigger Factor, assuming its role in cotranslational folding of nascent polypeptides also during low Mg2+. I will now elucidate the mechanism by which DnaK takes over cotranslational polypeptide folding from Trigger Factor during Mg2+ starvation; and identify the physiological benefits of this novel DnaK function. I will also examine how Mg2+ starvation changes the balance between the canonical DnaK/DnaJ/GrpE and GroEL/GroES chaperone systems that act on existing proteins because protein homeostasis involves not only synthesis of new proteins but also maintenance of existing proteins. By altering the activities of these two chaperone systems, S. Typhimurium is hypothesized to maintain certain proteins soluble and active, and other proteins insoluble and inactive. The starvation-induced transition to a slow growth state renders bacteria phenotypically resistant to antibacterial agents, hindering the cure of bacterial infections. The molecular and physiological results from this research will reveal novel control of chaperone-mediated adaptations in human pathogens. Moreover, the universal nature of Mg2+ dependence, chaperones, and protein homeostasis makes this study widely applicable to diverse organisms across all domains of life.

项目摘要 所有的生命形式都合成和维持蛋白质来进行基本的细胞过程。蛋白质合成 和维护需要巨大的能量和资源，包括Mg 2+，最丰富的二价 活细胞中的阳离子。微生物病原体在哺乳动物巨噬细胞内往往面临营养限制 并且必须恢复蛋白质稳态以在宿主组织中持续存在。我建议确定 兼性细胞内病原体肠道沙门氏菌鼠伤寒血清型（S.鼠伤寒） 使用分子伴侣来控制蛋白质稳态，从而使Mg 2 + 饥饿我发现了DnaK的两个新功能，DnaK是一种高度保守的分子伴侣， 在营养充足的条件下，与辅伴侣蛋白一起折叠蛋白质。首先，我确定， 令人惊讶的是，DnaK抑制蛋白质合成通过结合核糖体在一个cochaperone非依赖性 当S。鼠伤寒杆菌的Mg 2+含量较低，因此有助于节约能源和资源。 第二，我确定DnaK拮抗典型的核糖体相关伴侣触发因子， 因子，假定其在新生多肽的共翻译折叠中的作用也在低Mg 2+期间。我会 现在阐明DnaK从Trigger接管共翻译多肽折叠的机制 因子在Mg 2+饥饿;并确定这种新的DnaK功能的生理益处。我会 还研究了Mg 2+饥饿如何改变经典DnaK/DnaJ/GrpE之间的平衡， GroEL/GroES分子伴侣系统作用于现有蛋白质，因为蛋白质稳态不涉及 不仅合成新蛋白质，而且维持现有蛋白质。通过改变这些细胞的活动， 两个分子伴侣系统，S.鼠伤寒沙门氏菌被假设为维持某些蛋白质的可溶性和活性， 以及其他不溶和无活性的蛋白质。饥饿诱导的向缓慢生长状态的转变使得 细菌表型上对抗菌剂耐药，阻碍细菌感染的治愈。的 这项研究的分子和生理结果将揭示伴侣介导的新的控制， 适应人类病原体。此外，Mg 2+依赖性、伴侣蛋白和 蛋白质内稳态使这项研究广泛适用于所有生命领域的各种生物。