Understanding the importance of IkB-b as a selective co-activator of NF-kB signaling

项目总结/摘要 NF-κ B家族的转录因子是多种生物过程的中心调节因子。 这包括胚胎发育和细胞存活等基本事件， 先天性和适应性免疫系统的反应。仍然难以捉摸的是， 允许这五种蛋白质的有限集合来协调完全不同的转录程序， 这些不同的细胞功能所需要的。了解NF-κ B依赖性转录的细节， 然而，对于在以下情况下实现靶向治疗干预的努力至关重要： 病理性NF-κ B活化，如败血症、类风湿性关节炎和癌症。 微调NF-κ B活化的因素之一是NF-κ B的抑制剂，亚型B（IkB-B），其已被证实是NF-κ B的抑制剂。 显示出作为NF-kB的常规抑制剂和非典型共激活剂的有趣的双重作用， 依赖转录在未受刺激的细胞中，IkB-b在细胞质中螯合NF-kB二聚体，从而 阻止转录激活，而在刺激时，核形式的IkB-b增强转录， NF-kB依赖基因的子集。因此，IkB-b缺陷的巨噬细胞产生明显减少的 暴露于活化刺激后细胞因子TNF-α的水平，而细胞因子IL-6的水平 基本上不受影响。 本项目的目标是全面了解IkB-b作为NF-kB选择性共激活剂的作用 activation.这将通过严格表征IkB-b功能的基础机制来实现 在生物化学和分子水平上。此外，IkB-b共激活剂功能的完整程度及其作用 将使用尖端的基因组学技术，包括RNA-seq和ChIP， seq.然后将这些数据集整合以创建IkB-b功能的整体模型。最后，真正的 IkB-b的生理相关性将在体内用急性和慢性炎症的小鼠模型来确定。 炎症，以及细菌感染。

PROJECT SUMMARY/ABSTRACT The transcription factors of the NF-kB family are central regulators of a wide variety of biological processes. This includes events as fundamental as embryonic development and cellular survival as well as the intricate responses of the innate and adaptive immune system. What has remained elusive are the mechanisms that allow this limited set of five proteins to orchestrate the radically different transcriptional programs which are required for these disparate cellular functions. Understanding the details of NF-kB-dependent transcription, however, is of paramount importance for efforts to achieve targeted therapeutic intervention in cases of pathological NF-kB activation, such as sepsis, rheumatoid arthritis and cancer. One of the factors that fine-tune NF-kB activation is the inhibitor of NF-kB, isoform b (IkB-b), which has been shown to serve an intriguing dual role as a conventional inhibitor, and atypical co-activator, of NF-kB- dependent transcription. In unstimulated cells, IkB-b sequesters NF-kB dimers in the cytoplasm and thus prevents transcriptional activation, whereas upon stimulation a nuclear form of IkB-b enhances transcription of a subset of NF-kB-dependent genes. Consequently, IkB-b-deficient macrophages produce starkly reduced levels of the cytokine TNF-a following exposure to an activating stimulus, whereas levels of the cytokine IL-6 are largely unaffected. The goal of this project is to comprehensively understand the role of IkB-b as a selective co-activator of NF-kB activation. This will be accomplished by rigorously characterizing the mechanism that underlies IkB-b function on a biochemical and molecular level. Furthermore, the full extent of IkB-b co-activator function and its effect on global transcription will be probed using cutting-edge genomics techniques, including RNA-seq and ChIP- seq. These data sets will then be integrated to create a holistic model of IkB-b function. Finally, the true physiological relevance of IkB-b will be determined in vivo with mouse models of acute and chronic inflammation, as well as bacterial infection.