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）深刻影响不同生物（包括人类）的不同生物的压力抗性和寿命。众所周知，IIS通过抑制DAF-16/FOXO蛋白来促进衰老，但是我们的实验室已在秀丽隐杆线虫中显示，IIS也直接抑制了转录因子SKN-1，该因子在应激抗性中保守了功能。 SKN-1促进了寿命，并有助于与IIS减少有关的压力抗性和寿命增加。我们的表达分析表明，在正常条件下，SKN-1上调了许多应力防御和细胞修复过程中涉及的基因，并且可能直接抑制许多限制应激抗性或寿命的基因，包括某些IIS基因。相反，SKN-1通过诱导较小的排毒基因来应对压力。这些发现表明，SKN-1在促进寿命的基本机制中起着至关重要的作用，这使得了解其功能和受IIS的调节是至关重要的，并且在减少IIS时会影响生物体。该项目将通过抑制SKN-1来调节IIS如何调节基因表达，以及SKN-1如何促进对IIS降低的寿命和抗压力。基于微阵列的分析将用于鉴定SKN-1响应IIS降低并剖析SKN-1和DAF-16的效应，从而揭示了由SKN-1和IIS控制的过程和调节机制，从而鉴定SKN-1上调或下调的基因。我们通过染色质免疫沉淀在体内分析体内SKN-1 DNA结合的强大能力将用于识别和比较正常和IIS条件下SKN-1直接调节的基因。然后将检查代表性SKN-1靶基因的功能，这些功能将揭示SKN-1对这些IIS表型的过程，并可能识别新的寿命基因。此外，将研究SKN-1是否通过仅作用于肠，主要的解毒器官，还是受IIS影响的其他组织来促进IIS应力和寿命表型。还将确定SKN-1是否直接抑制寿命调节基因，以及其压力是否可以通过压力缓解其抑制活性。最后，将研究IIS对SKN-1的调节作用，首先通过对14-3-3蛋白PAR-5和FTT-2的分析进行分析。这些蛋白质可能是IIS信号的效应子，但对SKN-1进行了反对调节，par-5抑制SKN-1和FTT-2是所需的辅助因子。将研究这些14-3-3蛋白是否会响应IIS与SKN-1相互作用，以及FTT-2如何促进SKN-1核功能。此外，我们所经历的蛋白质组学方法将用于鉴定在正常和减少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：对增加生产寿命并预防慢性疾病的机制的理解可能会提供任何生物医学研究领域的最大成本/收益率。胰岛素信号传导的减少促进了多种生物体中代谢应激的寿命和抗性。该项目将使用强大的模型生物，线虫蠕虫秀丽隐杆线虫，以调查如何防御细胞损伤的机制的主调节器，毒素和毒素有助于减少胰岛素信号的有益作用，并由胰岛素信号通路控制。