Discovery of cGAS-like signaling enzymes in innate immunity and disease

项目摘要 人类细胞使用称为“RNA第二信使”的信号来刺激免疫反应， 疾病这些信号是响应病原体感染和细胞应激而产生的，并且对于 控制蜂窝通信。最近的证据表明，RNA第二信使信号 由酶环GMP-AMP合酶（cGAS）控制，是免疫应答的关键组分， 许多类型的癌症，从这些天然信号开发的药物类似物正在迅速出现， 有希望的新疗法这些药物强大的抗肿瘤潜力说明了发现的重要性 以及对自然发生的RNA第二信使信号的机械理解。 令人惊讶的是，我们的工作揭示了cGAS是我们命名的信号传导酶大家族的一部分， cGAS/DncV样核苷酸转移酶（CD-NTase）和许多RNA第二信使途径 在人类生物学中还有待发现。潜在的人CD-NT酶包括未表征的免疫cGAS- 就像以前被认为是癌症中经常突变的基因的受体一样。结果表明，RNA 第二信使信号通路是一个新的丰富的研究领域，可能会影响许多领域的基础 人类生物学和疾病。我们开发了一种创新的方法来揭示这些功能， 酶和发现负责信号传导的生物学和天然产物。 我们提出的研究将提供一个新的详细了解的酶，控制RNA第二 信使信号，并使发现全新的RNA信号类别。具体而言，建议 实验将使用全国范围内的CD-NTase酶分析，以确定特定的RNA的机制， 产物合成，X射线晶体学，以确定后生动物CD-NT酶的结构和分子基础 功能，以及一套创新的细胞生物学实验，使用新鉴定的CD-NTase RNA信号， 直接细胞刺激和化学蛋白质组学。我们的实验将确定新发现的 cGAS样酶在人类生物学中的作用，并解释了允许RNA第二信使 控制下游细胞反应。

Project Summary Human cells use signals called "RNA second messengers" to stimulate the immune response and prevent disease. These signals are produced in response to pathogen infection and cellular stress, and are important for controlling cellular communication. Recent evidence demonstrates that RNA second messenger signaling controlled by the enzyme cyclic GMP–AMP synthase (cGAS) is a critical component of the immune response to many types of cancer, and drug analogues developed from these natural signals are rapidly emerging as promising new treatments. The potent antitumor potential of these drugs illustrates the importance of discovery and mechanistic understanding of naturally occurring RNA second messenger signals. Surprisingly, our work has revealed that cGAS is part of a broad family of signaling enzymes we named cGAS/DncV-like nucleotidyltransferase (CD-NTase) enzymes, and many RNA second messenger pathways remain to be discovered in human biology. Potential human CD-NTases include uncharacterized immune cGAS- like receptors previously implicated as genes frequently mutated in cancer. Our results demonstrate that RNA second messenger signaling pathways are a new rich area of research and likely impact many areas of basic human biology and disease. We have developed an innovative approach to uncover the function of these enzymes and discover the biology and natural products responsible for signaling. Our proposed research will provide a new detailed understanding of the enzymes that control RNA second messenger signaling and enable discovery of entirely new classes of RNA signals. Specifically, the proposed experiments will use kingdom-wide analysis of CD-NTase enzymes to determine the mechanism of specific RNA product synthesis, X-ray crystallography to define the structural and molecular basis of metazoan CD-NTase function, and an innovative set of cell biology experiments using newly identified CD-NTase RNA signals for direct cell stimulation and chemical-proteomics. Our experiments will define the function of newly discovered cGAS-like enzymes in human biology and explain the molecular rules that allow RNA second messengers to control downstream cellular responses.