Regulation of SKN-1 functions by insulin-like signaling in C. elegans

线虫中胰岛素样信号传导对 SKN-1 功能的调节

• 批准号: 8245740
• 负责人: T Keith Blackwell
• 金额: $ 36.45万
• 依托单位: JOSLIN DIABETES CENTER
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-03 至 2014-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8245740
• 关键词: 14-3-3 Proteins; Address; Affect; Aging; Animal Model; Animals; Area; Biological; Biological Assay; Biological Process; Biomedical Research; Caenorhabditis elegans; Candidate Disease Gene; Chronic Disease; Costs and Benefits; DNA Binding; Data; Drug Metabolic Detoxication; Feedback; Gene Components; Gene Expression; Gene Targeting; Genes; Genome; Human; Insulin; Insulin Signaling Pathway; Insulin-Like Growth Factor I; Intestines; Investigation; Longevity; Metabolic stress; Modeling; Molecular Profiling; Nematoda; Nuclear; Organ; Organism; Pathway interactions; Phenotype; Phosphorylation; Play; Process; Proteins; Proteomics; RNA Polymerase II; Receptor Signaling; Regulation; Regulator Genes; Resistance; Role; Signal Pathway; Signal Transduction; Stress; Testing; Tissues; Toxin; Work; acute stress; base; biological adaptation to stress; chromatin immunoprecipitation; cofactor; experience; in vivo; insulin signaling; interest; longevity gene; mutant; nrf1 protein; public health relevance; repaired; response; transcription factor

DESCRIPTION (provided by applicant): Insulin/IGF-1 signalling (IIS) profoundly influences stress resistance and longevity in diverse organisms, possibly including humans. It is well known that IIS promotes aging by inhibiting DAF-16/FOXO proteins, but our lab has shown in C. elegans that IIS also directly inhibits the transcription factor SKN-1, which has conserved functions in stress resistance. SKN-1 promotes longevity, and contributes to stress resistance and longevity increases that are associated with reduced IIS. Our expression profiling shows that under normal conditions SKN-1 upregulates genes involved in many stress defense and cellular repair processes, and may directly repress numerous genes that limit stress resistance or longevity, including some IIS genes. In contrast, SKN-1 responds to stress by inducing a smaller group of detoxification genes. These findings show that SKN-1 plays a critical role in fundamental mechanisms that promote longevity, making it of major significance to understand how it functions and is regulated by IIS, and affects the organism when IIS is reduced. This project will investigate how IIS regulates gene expression by inhibiting SKN-1, and how SKN-1 promotes longevity and stress resistance in response to IIS reductions. Microarray-based profiling will be used to identify genes that are either up- or down-regulated by SKN-1 in response to reduced IIS, and to dissect effects of SKN-1 and DAF-16, thereby revealing processes and regulatory mechanisms that are controlled by both SKN- 1 and IIS. Our robust capability to analyze SKN-1 DNA binding in vivo by chromatin immunoprecipitation will be used to identify and compare genes that are directly regulated by SKN-1 under normal and IIS conditions. The functions of representative SKN-1 target genes will then be examined, work that will reveal processes through which SKN-1 contributes to these IIS phenotypes, and is likely to identify new longevity genes. Additionally, it will be investigated whether SKN-1 contributes to IIS stress and longevity phenotypes by acting only in the intestine, the major detoxification organ, or also in other tissues that are influenced by IIS. It will also be determined conclusively whether SKN-1 directly represses longevity-regulatory genes, and whether its repressive activity is relieved by stress. Finally, the regulatory effects of IIS on SKN-1 will be studied, first through an analysis of the 14-3-3 proteins PAR-5 and FTT-2. These proteins are likely effectors of IIS signals but regulate SKN-1 oppositely, with PAR-5 inhibiting SKN-1 and FTT-2 being a required cofactor. It will be investigated whether these 14-3-3 proteins interact with SKN-1 in response to IIS, and how FTT-2 might promote SKN-1 nuclear functions. In addition, proteomic approaches with which we are experienced will be used to identify proteins that associate with SKN-1 under normal and reduced IIS conditions, and may regulate its activities. PUBLIC HEALTH RELEVANCE: An understanding of mechanisms that increase productive lifespan and protect against chronic disease may provide the greatest cost/benefit ratio of any area of biomedical research. Reductions in insulin signalling promote longevity and resistance to metabolic stresses in diverse organisms. This project will use a powerful model organism, the nematode worm C. elegans, to investigate how a master regulator of mechanisms that defend against cellular damage and toxins contributes to the beneficial effects of reducing insulin signalling, and is itself controlled by the insulin signalling pathway.

描述（由申请人提供）：胰岛素/IGF-1 信号传导 (IIS) 深刻影响多种生物体（可能包括人类）的应激抵抗力和寿命。众所周知，IIS通过抑制DAF-16/FOXO蛋白来促进衰老，但我们的实验室在秀丽隐杆线虫中发现，IIS还直接抑制转录因子SKN-1，该因子具有保守的抗应激功能。 SKN-1 可以延长寿命，并有助于抗压能力和寿命的延长，而这与 IIS 的减少有关。我们的表达谱显示，在正常条件下，SKN-1 上调参与许多应激防御和细胞修复过程的基因，并可能直接抑制许多限制应激抵抗或寿命的基因，包括一些 IIS 基因。相比之下，SKN-1 通过诱导一小群解毒基因来应对压力。这些发现表明，SKN-1 在促进长寿的基本机制中发挥着关键作用，这使得了解 SKN-1 如何发挥作用、受 IIS 调节以及当 IIS 减少时如何影响生物体具有重要意义。该项目将研究 IIS 如何通过抑制 SKN-1 来调节基因表达，以及 SKN-1 如何响应 IIS 的减少而促进寿命和抗应激能力。基于微阵列的分析将用于识别因 IIS 减少而被 SKN-1 上调或下调的基因，并剖析 SKN-1 和 DAF-16 的影响，从而揭示由 SKN-1 和 IIS 控制。我们通过染色质免疫沉淀分析体内 SKN-1 DNA 结合的强大能力将用于识别和比较在正常和 IIS 条件下直接受 SKN-1 调节的基因。然后将检查代表性 SKN-1 靶基因的功能，这项工作将揭示 SKN-1 促成这些 IIS 表型的过程，并可能识别新的长寿基因。此外，还将研究 SKN-1 是否通过仅作用于主要解毒器官肠道或受 IIS 影响的其他组织来促进 IIS 应激和长寿表型。还将最终确定 SKN-1 是否直接抑制长寿调节基因，以及其抑制活性是否会因压力而缓解。最后，将首先通过分析 14-3-3 蛋白 PAR-5 和 FTT-2，研究 IIS 对 SKN-1 的调节作用。这些蛋白质可能是 IIS 信号的效应器，但相反地调节 SKN-1，其中 PAR-5 抑制 SKN-1，FTT-2 是必需的辅助因子。我们将研究这些 14-3-3 蛋白是否与 SKN-1 相互作用以响应 IIS，以及 FTT-2 如何促进 SKN-1 核功能。此外，我们经验丰富的蛋白质组学方法将用于鉴定在正常和降低的 IIS 条件下与 SKN-1 相关的蛋白质，并可能调节其活性。 公共卫生相关性：了解延长生产寿命和预防慢性疾病的机制可能会提供生物医学研究任何领域中最大的成本/效益比。胰岛素信号传导的减少可促进多种生物体的寿命和对代谢应激的抵抗力。该项目将使用一种强大的模型生物——线虫秀丽隐杆线虫，来研究防御细胞损伤和毒素机制的主调节器如何有助于减少胰岛素信号传导的有益作用，并且其本身受胰岛素信号传导通路控制。