Role of FIP200 in RIG-I-mediated innate immunity

FIP200 在 RIG-I 介导的先天免疫中的作用

• 批准号: 10295767
• 负责人: Shitao Li
• 金额: $ 34.2万
• 依托单位: TULANE UNIVERSITY OF LOUISIANA
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-11-15 至 2023-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10295767
• 关键词: Antiviral Agents; Autoimmune Diseases; Autophagocytosis; Bioinformatics; Caspase; Cells; Communicable Diseases; Data; Dimerization; Double-Stranded RNA; Embryo; Family; Fibroblasts; Genes; Goals; Grant; Host Defense Mechanism; Human; Immune system; Innate Immune Response; Interferon Activation; Interferon Type I; Interferons; Interphase Cell; Knock-out; Knockout Mice; Knowledge; Ligands; Literature; Mediating; Molecular; Mus; Natural Immunity; Nucleic Acids; PTK2 gene; Phosphorylation; Pilot Projects; Production; Protein Dephosphorylation; Protein phosphatase; Proteins; Proteomics; RNA; RNA Virus Infections; RNA Viruses; Regulation; Resistance; Role; Signal Pathway; Signal Transduction; Specificity; Tretinoin; Vesicular stomatitis Indiana virus; Viral; Viral Load result; Virus Diseases; Virus Replication; base; conditional knockout; cytokine; dimer; in vivo; insight; macrophage; monocyte; mouse model; novel; novel therapeutic intervention; prevent; protein complex; recruit; response; sensor; therapy design; tripolyphosphate

Project summary Retinoic acid-inducible gene I (RIG-I) is an intracellular sensor for recognition of viral double-stranded RNA (dsRNA) and 5` triphosphate RNA. Following RNA recognition, RIG-I induces a robust production of type I interferons (IFN). To prevent aberrant IFN expression, RIG-I activation is regulated by several steps, including dephosphorylation and oligomerization of the CARD domain of RIG-I. Phosphorylation of the CARD domain retains RIG-I inactive in the resting cells. Upon RNA ligand engagement, RIG-I is dephosphorylated by the protein phosphatase 1 (PP1), which permits subsequent oligomerization for activation. However, PP1 has numerous substrates in the cell and what determines the specificity of PP1 towards RIG-I is unknown. Furthermore, how dephosphorylation facilitates RIG-I oligomerization is not clear. Thus, there is a critical need to define the regulatory mechanisms for the dephosphorylation and oligomerization of RIG-I. Elucidation of these mechanisms will not only reveal a novel regulatory mechanism of host defense, but also provide insights for developing novel therapeutic strategies to prevent aberrant IFN activation. The long-term goal of our lab is to understand the regulatory mechanisms of nucleic acid-elicited innate immunity. The overall objective of this proposal is to investigate the regulatory mechanisms for RIG-I-mediated innate immunity. Our pilot proteomics study found that RIG-I interacted with FIP200 (FAK-family interacting protein of 200 kDa), a well-known autophagy protein. Autophagy has a crosstalk with innate immunity and several autophagy genes suppress RIG-I signaling pathway. However, to our surprise, deficiency of FIP200 abolishes 5` triphosphate RNA and dsRNA-induced type I IFN expression and promotes RNA virus replication, such as the vesicular stomatitis virus (VSV). Interestingly, FIP200 is also known as the PP1 regulatory subunit 131 (PPP1R131), but its role in PP1 dephosphorylation is unknown. Based on the existing literature and our preliminary data, we propose the central hypothesis that FIP200 is essential for dsRNA-mediated innate immunity by regulating RIG-I dephosphorylation and oligomerization. We will investigate the following aims: Aim 1: Determine the molecular basis for the role of FIP200 in RIG-I signaling pathway. Aim 2: Determine the mechanisms by which FIP200 promotes RIG-I activation. Aim 3: Determine the in vivo interaction between FIP200 and RIG-I using a mouse model. Dysregulation of IFN responses can result in decreased resistance to viral infection or detrimental effects due to an overactive immune system. This proposal investigates the molecular mechanisms by which FIP200 controls innate immune responses to viral infection. The mechanistic concepts derived from this proposal will not only fill the knowledge gap on RIG-I regulation, but also provide insights for antiviral therapeutics.

项目概要 视黄酸诱导基因 I (RIG-I) 是一种细胞内传感器，用于识别病毒双链 RNA (dsRNA) 和 5` 三磷酸 RNA。 RNA 识别后，RIG-I 诱导 I 型的大量产生 干扰素（IFN）。为了防止异常的 IFN 表达，RIG-I 激活通过几个步骤进行调节，包括 RIG-I 的 CARD 结构域的去磷酸化和寡聚化。 CARD 结构域的磷酸化 使 RIG-I 在静息细胞中保持非活性状态。在 RNA 配体结合后，RIG-I 被去磷酸化 蛋白磷酸酶 1 (PP1)，允许随后进行寡聚化以进行激活。然而，PP1有 细胞中存在多种底物，决定 PP1 对 RIG-I 的特异性的因素尚不清楚。 此外，去磷酸化如何促进 RIG-I 寡聚化尚不清楚。因此，迫切需要 定义 RIG-I 去磷酸化和寡聚化的调控机制。阐明 这些机制不仅揭示了宿主防御的新型调节机制，而且提供了见解 开发新的治疗策略以防止异常的 IFN 激活。 我们实验室的长期目标是了解核酸引发的先天性调控机制 免疫。该提案的总体目标是研究 RIG-I 介导的调节机制 先天免疫。我们的试点蛋白质组学研究发现 RIG-I 与 FIP200 相互作用（FAK 家族相互作用） 200 kDa 的蛋白质），一种著名的自噬蛋白。自噬与先天免疫有串扰， 一些自噬基因抑制 RIG-I 信号通路。然而，令我们惊讶的是，FIP200 的缺陷 消除 5` 三磷酸 RNA 和 dsRNA 诱导的 I 型 IFN 表达并促进 RNA 病毒复制， 例如水泡性口炎病毒（VSV）。有趣的是，FIP200也被称为PP1调节亚基 131 (PPP1R131)，但其在 PP1 去磷酸化中的作用尚不清楚。根据现有文献和我们的 根据初步数据，我们提出了中心假设：FIP200 对于 dsRNA 介导的先天性至关重要 通过调节 RIG-I 去磷酸化和寡聚化来免疫。我们将研究以下目标： 目标 1：确定 FIP200 在 RIG-I 信号通路中作用的分子基础。 目标 2：确定 FIP200 促进 RIG-I 激活的机制。 目标 3：使用小鼠模型确定 FIP200 和 RIG-I 之间的体内相互作用。 干扰素反应失调可导致对病毒感染的抵抗力下降或由于以下原因产生有害影响： 过度活跃的免疫系统。该提案研究了 FIP200 的分子机制 控制对病毒感染的先天免疫反应。从该提案中得出的机械概念将 不仅填补了 RIG-I 调控的知识空白，而且为抗病毒治疗提供了见解。