Mechanistic analysis of a posttranslationally modified innate antiviral effector

流感和其他新出现的病毒代表了世界范围内的主要健康问题， 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。这些基因中的一些编码蛋白质， 抗病毒活性，尽管这些蛋白质中只有一小部分已经被机械地表征。 在这些蛋白质中，干扰素诱导型跨膜蛋白3（IFITM3）最近已被证明是由 美国和其他国家对所有测试的流感病毒亚型以及一些 其他病毒家族。此外，这种蛋白质在干扰素效应物中是独特的，因为它似乎起作用于 通过阻止病毒进入或融合而不是抑制病毒复制。使用化学报告，我们 已经表明IFITM3是后脂肪棕榈酰化的，这种脂质修饰调节其抗病毒活性， 活动此外，我们的初步数据表明IFITM3也是泛素化的。的总体目标 拟议的研究是通过描述机制来增加对先天抗病毒免疫的理解， IFITM3的作用及其通过翻译后修饰的细胞调节。在K99阶段， 开发生物化学和显微镜分析，以测试棕榈酰化控制适当的假设， IFITM3的运输允许其与病毒颗粒相互作用并防止病毒进入。有了这些知识， 另一方面，我们将在R00阶段寻找鉴定负责IFITM3棕榈酰化的酶，并观察 病毒感染期间棕榈酰化酶的整体转录调节。此外，我们将 应用在K99阶段开发的测定来了解泛素化在IFITM3生物学中的作用及其 与棕榈酰化相互作用。分析IFITM3的作用机制和通过一种新的方法来控制这种活性。 一组独特的翻译后修饰可能为利用I型糖尿病的力量提供必要的见解， 干扰素用于对抗病毒病原体。

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.