Structural Regulation of IRF3 Activation and Association with Co-activators of the IFN Beta Enhanceosome

项目摘要 接触病毒后，免疫系统激活并迅速采取措施保护身体免受感染。 一种正在蔓延的传染病我们对导致免疫激活的信号级联反应的理解 对于设计有效的治疗药物来调节这一过程至关重要。细胞表面和 胞质受体识别病原体特异性分子，例如激活细胞内的 干扰素调节因子3（IRF 3），它是免疫激活的主要调节因子。一旦激活，IRF 3 促进干扰素β（IFNβ）的表达，这是抗病毒反应所必需的。尽管IRF 3 在抗病毒反应中起积极作用，IRF 3表达失调与多种自身免疫性疾病有关。 疾病IFNβ的严格调节对于最大限度地减少受感染宿主的不受控制的炎症损伤至关重要 同时清除感染IRF 3与ATF 2/c-Jun、p65/p50和IRF 7一起形成高级分子， 这种复合物称为IFNβ增强体，严格调节IFNβ的表达。虽然《公约》的原则 信号通路，激活IRF 3和诱导IFNβ的表达，结构的见解， IRF 3和IFNβ增强体组装的激活仍然很少。在这份提案中，我试图描述 通过使用X射线晶体学研究IRF 3激活的结构机制。然后，我将使用低温电子 显微镜下观察以表征促进IRF 3与p65在增强体处相互作用的结构特征。 这些研究将为了解其他IRF如何被激活以及其他增强体如何被激活提供新的见解。 复合体组装。最重要的是，IRF 3激活和与p65组装的基于结构的分析， 将为设计可直接靶向激活的小分子调节剂提供基础， IRF 3的抑制分别响应于病毒感染和自身免疫性疾病。 !

PROJECT SUMMARY Following exposure to a virus, the immune system activates and takes rapid measures to protect the body from a spreading infection. Our understanding of the signaling cascade that leads to immuno-activation in response to viral infections is crucial for designing efficient therapeutic drugs that regulate this process. Cell surface and cytosolic receptors recognize pathogen-specific molecules such as viral nucleic acids that activate the interferon regulator factors 3 (IRF3), which is a master regulator of immune activation. Once activated, IRF3 promotes the expression of interferon β (IFNβ), which is essential for the antiviral response. Despite IRF3's active role in antiviral response, dysregulation in IRF3 expression has been implicated in multiple autoimmune diseases. Strict regulation of IFNβ is critical to minimize uncontrolled inflammation damage to infected hosts while clearing the infection. Together with ATF2/c-Jun, p65/p50, and IRF7, IRF3 form a higher order molecular complex called the IFNβ enhanceosome to strictly regulate IFNβ expression. While the principles of the signaling pathway that activates IRF3 and induces IFNβ expression are established, structural insights into the activation of IRF3 and IFNβ enhanceosome assembly remain scarce. In this proposal, I seek to characterize the structural mechanism of IRF3 activation by using X-ray crystallography. Then, I will use cryo-electron microscopy to characterize the structural features promoting IRF3 interactions with p65 at the enhanceosome. These studies will provide insights into how the other IRFs get activated and how other enhanceosome complexes assemble. Most importantly, structural-based analyses of IRF3 activation and assembly with p65 will provide a basis for designing small molecule modulators that can directly target the activation and suppression of IRF3 in response to viral infections and autoimmune diseases, respectively. !