Regulatory Dynamics of the Proteostasis Network

蛋白质稳态网络的调控动态

• 批准号: 10210948
• 负责人: David Pincus
• 金额: $ 32.2万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-13 至 2025-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10210948
• 关键词: Alanine; Alzheimer' s Disease; Amino Acids; Architecture; Binding; Binding Sites; Biochemistry; Biological Assay; C-terminal; Cancer Cell Growth; Cell Death; Cell physiology; Cells; Cellular Stress; Cellular biology; Complex; Cytosol; DNA; DNA Binding; Defect; Disease; Ensure; Equilibrium; Eukaryota; Event; Feedback; Gene Expression; Genes; Genetic Transcription; Goals; HSF1; Heart; Heat-Shock Response; Human; Huntington Disease; Laboratories; Lead; Life; Ligands; Link; Maintenance; Malignant Neoplasms; Mediating; Mission; Modeling; Molecular; Molecular Chaperones; Molecular Genetics; Monitor; Mutation; N-terminal; Nerve Degeneration; Neurodegenerative Disorders; Nucleoplasm; Organelles; Orphan; Parkinson Disease; Pathology; Protein Biosynthesis; Proteins; Quality Control; Recombinant Proteins; Regulation; Repression; Research; Ribosomal Proteins; Ribosomes; Saccharomycetales; Series; Signal Transduction; Site; Stress; Surface; Surveys; Systems Biology; Tail; Testing; Therapeutic; Threonine; Transactivation; Transcriptional Regulation; United States National Institutes of Health; Work; Yeasts; cancer cell; cell growth; chromatin immunoprecipitation; cytotoxic; experimental study; fitness; human disease; insight; mutant; novel; overexpression; premature; programs; protein aggregation; protein folding; protein misfolding; proteostasis; rapid growth; response; tool; transcription factor; tumor progression

PROJECT SUMMARY / ABSTRACT Cancer and neurodegeneration are often thought to be on opposing ends of the disease spectrum – the former characterized by unchecked cell growth and the latter by premature cell death. However, they are linked by dysregulation of a common underlying cellular state: protein homeostasis (proteostasis). Proteostasis refers to the dynamic balance of protein synthesis, folding and degradation, the maintenance of which is required for the vast majority of cellular processes. Defects in proteostasis lead to protein aggregation, a hallmark of neurodegenerative diseases such as Alzheimer’s, Parkinson’s, Huntington’s and ALS. Conversely, many cancer cells overexpress proteostasis machinery to counteract high mutational loads. The long-term goal of my research program is to define the mechanisms that healthy cells employ to maintain proteostasis and to establish how this regulation breaks down and is hijacked in disease. The central regulatory axis of the proteostasis network (PN) is the heat shock response (HSR), a universally conserved gene expression program under the control of transcription factor Hsf1 in eukaryotes. Despite its identification 30 year ago, the mechanisms that control Hsf1 activity and thereby expression of the HSR have remained elusive. Recent work from my laboratory using budding yeast revealed a key feedback loop that governs Hsf1 activity. We found that the chaperone Hsp70 represses Hsf1 in unstressed cells and that Hsf1-mediated induction of Hsp70 is requied to deactivate Hsf1. Thus, Hsf1 and Hsp70 constitute a feedback loop that promotes homeostatic adaptation to stress This proposal builds upon this discovery and the tools and assays we have developed to answer major outstanding questions concerning Hsf1 regulation. In Aim 1 we will define the upstream signaling events that activate Hsf1. We hypothesize that ribosome-nascent chain complexes with C-terminal alanine/threonine extensions (“CAT-tails”) and newly synthesized “orphan” ribosomal proteins (oRPs) trigger the HSR by sequestering the Hsp70 co-chaperone Sis1 away from Hsf1. In Aim 2 we will define the molecular mechanisms by which Hsp70 represses Hsf1. We will test the hypothesis that Hsp70 represses Hsf1 both by inhibiting Hsf1 DNA binding and by blocking Hsf1-mediated transactivation. In Aim 3 we will reveal novel feedback loops that control Hsf1. We will systematically determine the contribution of all Hsf1 targets to wild-type Hsf1 activation dynamics. By undertaking a multi-faceted analysis of the HSR – combining cell biology, molecular genetics, biochemistry and systems biology – we will establish the signals, regulatory mechanisms and feedback loops that govern this central adaptive circuit that lies at the heart of human diseases as diverse as cancer and neurodegeneration.

项目总结/摘要 癌症和神经退行性变通常被认为是疾病谱的两端- 前者的特征是细胞生长不受抑制，后者的特征是细胞过早死亡。然而，它们是相互关联的。 通过一种常见的潜在细胞状态的失调：蛋白质稳态（proteostasis）。蛋白质稳态是指 蛋白质合成、折叠和降解的动态平衡， 绝大多数的细胞过程。蛋白质稳态的缺陷导致蛋白质聚集，这是蛋白质稳态的标志。 神经退行性疾病，如阿尔茨海默氏症、帕金森氏症、亨廷顿氏症和ALS。相反，许多 癌细胞过度表达蛋白质稳定机制以抵消高突变负荷。我的长期目标是 研究计划是确定健康细胞维持蛋白质稳态的机制， 确定这种调节是如何在疾病中被破坏和劫持的。 蛋白质稳态网络（PN）的中心调节轴是热休克反应（HSR）， 在真核生物中转录因子Hsf 1控制下的普遍保守的基因表达程序。 尽管它在30年前被发现，但控制Hsf 1活性从而表达Hsf 1的机制仍然是未知的。 HSR仍然难以捉摸。我的实验室最近使用芽殖酵母的工作揭示了一个关键的反馈 控制Hsf 1活性的环。我们发现，在未应激的细胞中，伴侣蛋白Hsp 70抑制Hsf 1， Hsf 1介导的Hsp 70的诱导是使Hsf 1失活所必需的。因此，Hsf 1和Hsp 70构成了一个 一个促进对压力的自我平衡适应的反馈回路 这项建议建立在这一发现以及我们开发的工具和测定方法的基础上， 有关HSF 1监管的未决问题。在目标1中，我们将定义上游信号事件， 激活Hsf 1。我们假设核糖体新生链与C-末端丙氨酸/苏氨酸复合物 新合成的“孤儿”核糖体蛋白（oRPs）通过以下方式触发HSR： 将Hsp 70共伴侣Sis 1与Hsf 1隔离。在目标2中，我们将定义分子机制 Hsp 70抑制Hsf 1。我们将检验Hsp 70抑制Hsf 1的假设，即Hsp 70通过抑制Hsf 1 DNA结合和阻断Hsf 1介导的反式激活。在目标3中，我们将揭示新的反馈回路， 对照Hsf 1。我们将系统地确定所有Hsf 1靶点对野生型Hsf 1激活的贡献， 动力学通过对HSR进行多方面的分析-结合细胞生物学，分子遗传学， 生物化学和系统生物学-我们将建立信号，调节机制和反馈回路 控制着这个中央适应性回路，这个回路是人类疾病的核心， 神经变性