The Expanded Repertoire of cGAMP Signal Transduction During Innate Immune Responses

项目摘要/摘要 致癌的DNA病毒感染占人类癌症的12%，是导致癌症的主要原因 世界各地的死亡率和发病率。治疗病毒感染的新疗法的发展 如果详细了解寄主对这种传染性侮辱的反应，将会大大受益。这个 免疫系统对抗病毒感染的能力通常是通过一系列复杂的 与病毒核酸结合的蛋白质。作为对来自病毒的DNA的反应，宿主蛋白环状GMP- AMP(CGAMP)合成酶(CGAS)产生信号核苷酸cGAMP，引发宿主炎症 通过结合干扰素基因的蛋白刺激物(STING)清除感染。然而，第二 信使信号转导系统通常依赖于各种蛋白质受体来驱动细胞反应。 CGAMP是否能超越刺激性激活而抑制病毒感染和肿瘤发生仍有待研究 很大程度上是未知的。最近的研究表明，cGAS和STING可以对 感染结局，表明cGAS在应对病毒感染中除信号外还发挥着多种作用 通过斯汀。为了系统地解决这一假设，我们产生了涂有cGAMP的珠子 能够从细胞提取液中分离cGAMP结合蛋白。使用这种方法，我们已经确定了两个新的 可以与cGAMP结合的除STING以外的蛋白质。这些新的cGAMP结合蛋白在 调节宿主对感染反应的细胞过程，包括细胞如何产生能量 以及生物合成构件，病毒依赖的细胞生理学的基本方面 以便于复制。在这里，我建议利用结构-功能分析结合生化和 用于询问这些先前未识别的cGAMP结合的生物学相关性的感染模型 蛋白质，并详细说明它们对病毒限制的影响。这些研究的结果将显著地为 宿主免疫系统可以限制病毒感染和肿瘤发生的机制，并可能提供 与传染病和恶性疾病作斗争的新治疗策略。

PROJECT SUMMARY/ABSTRACT Infections with oncogenic, DNA viruses account for twelve percent of human cancers and are a major cause of mortality and morbidity throughout the world. The development of new therapeutics to treat viral infections would significantly benefit from a detailed understanding of the host response to this infectious insult. The ability of the immune system to counteract viral infection is often mediated through a sophisticated repertoire of proteins that bind to viral nucleic acids. In response to DNA derived from viruses, the host protein cyclic GMP- AMP (cGAMP) Synthase (cGAS) produces the signaling nucleotide cGAMP, which initiates host inflammation to clear infection by binding to the protein Stimulatory of Interferon Genes (STING). However, second messenger signal transduction systems often rely on a variety of protein receptors to drive cellular responses. Whether cGAMP can function beyond STING activation to restrict viral infection and oncogenesis remains largely unknown. Recent studies have shown that cGAS and STING can have non-overlapping effects on infection outcome, suggesting that cGAS plays multiple roles in response to viral infection beyond signaling through STING. To systematically address this hypothesis, we have generated beads coated in cGAMP that are able to isolate cGAMP-binding proteins from cell extracts. Using this method, we have identified two new proteins other than STING that can bind to cGAMP. These novel cGAMP binding proteins have known roles in regulating cellular processes involved in the host response to infection including how the cell produces energy as well as biosynthetic building blocks, fundamental aspects of cellular physiology that viruses rely upon in order to facilitate replication. Here, I propose to utilize structure-function analysis coupled with biochemical and infection models to interrogate the biological relevance of these previously unrecognized cGAMP-binding proteins and detail their effects on viral restriction. The findings from these studies will significantly inform the mechanisms by which the host immune system can restrict viral infection and oncogenesis and may provide new therapeutic strategies to combat infectious and malignant diseases.