Mechanistic analysis of a posttranslationally modified innate antiviral effector

流感和其他新出现的病毒是世界范围内主要的健康问题，目前的战略是 疾病的预防或治疗是不够的。I型干扰素是一种诱导抗病毒状态的细胞因子 在细胞中，通过转录上调数百个基因。其中一些基因直接编码蛋白质 抗病毒活性，尽管只有一小部分这些蛋白质被机械地表征。 在这些蛋白质中，干扰素诱导的跨膜蛋白3(IFITM3)最近被发现 美国和其他国家对所有亚型流感病毒测试以及一些 其他病毒家族的成员。此外，这种蛋白质在干扰素效应器中是独一无二的，因为它似乎起作用 通过阻止病毒进入或融合，而不是抑制病毒复制。使用化学记者，我们 已经证明IFITM3是翻译后棕榈酰化的，这种脂质修饰调节其抗病毒作用 活动。此外，我们的初步数据表明，IFITM3也是泛素化的。该计划的总体目标 建议的研究是通过表征机制来增加对先天抗病毒免疫的理解。 翻译后修饰对IFITM3的作用及其细胞调控的影响。在K99阶段，我们将 发展生化和显微镜分析来验证棕榈酰化控制适当的假说 IFITM3的贩运使其能够与病毒颗粒相互作用并防止病毒进入。有了这方面的知识 手，然后我们将寻求在R00阶段，以确定负责IFITM3棕榈酰化的酶并查看 病毒感染过程中棕榈酰化酶的整体转录调控。此外，我们还将 应用K99阶段开发的分析方法来了解泛素化在IFITM3生物学中的作用及其 与棕榈酰化相互作用。分析IFITM3的作用机制及其对该活性的控制 一组独特的翻译后修饰可能会为驾驭类型I的力量提供必要的见解 用于对抗病毒病原体的干扰素。

Influenza and other emerging viruses represent major health concerns worldwide, and current strategies for prevention or treatment of disease are insufficient. Type I interferon is a cytokine that induces an antiviral state in cells by transcriptionally upregulating hundreds of genes. Some of these genes encode proteins with direct antiviral activity, though only a small number of these proteins have been mechanistically characterized. Among these proteins, the interferon-inducible transmembrane protein 3 (IFITM3) has been recently shown by us and others to have broad antiviral activity against all subtypes of influenza virus tested as well as a number of other virus families. Furthermore, this protein is unique among interferon effectors in that it appears to act by preventing entry or fusion of viruses rather than inhibiting viral replication. Using chemical reporters, we have shown that IFITM3 is post-translationally palmitoylated and this lipid modification regulates its antiviral activity. Furthermore, our preliminary data indicate that IFITM3 is also ubiquitinated. The overall goal of the proposed research is to increase understanding of innate antiviral immunity by characterizing the mechanism of action of IFITM3 and its cellular regulation by post-translational modifications. In the K99 phase, we will develop biochemical and microscopy assays to test the hypothesis that palmitoylation controls proper trafficking of IFITM3 allowing it to interact with viral particles and prevent viral entry. With this knowledge in hand we will then seek in the R00 phase to identify enzymes responsible for IFITM3 palmitoylation and look at the global transcriptional regulation of palmitoylating enzymes during viral infections. Furthermore, we will apply assays developed in the K99 phase to understand the role of ubiquitination in IFITM3 biology and its interplay with palmitoylation. Analyzing the mechanism of action of IFITM3 and the control of this activity by a unique set of post-translational modifications may provide insights necessary for harnessing the power of type I interferon for combating viral pathogens.