Function of the Sts protein phosphodiesterase domain

项目总结 Sts蛋白(Sts-1和Sts-2)负性调节哺乳动物免疫细胞内的信号通路 系统。缺乏Sts表达的小鼠(Sts-/-)对临床相关真菌和 细菌病原体，包括白色念珠菌、图拉氏弗朗西斯菌和金黄色葡萄球菌。抵抗力 与病原体快速清除和减少炎症有关。我们最近发现了一部小说， 与功能相关的Sts-1的磷酸二酯酶(PDE)活性。我们假设这是 史无前例的活性在调节免疫细胞信号通路中起着关键作用。为了实现我们的长期目标 为了开发新的传染病治疗方法，这项提议的目的是阐明信号转导 Sts-1 PDE结构域的作用并确定其功能的分子决定因素。以强劲的前期工作为指导 数据，我们将检验我们的假设，并通过追求以下两个具体目标来实现我们的总体目标： 1)阐明Sts PDE结构域在负调控免疫细胞信号通路中的作用； 2)鉴定底物，确定Sts PDE结构域功能的分子决定因素。 在第一个目标中，我们将利用基于细胞和动物的模型来评估Sts-1 PDE结构域的功能。在 第二个目标是，我们将使用靶向、基于动力学的方法和全球代谢组学来定义Sts-1 PDE 结构域底物的广度和特异性。此外，我们还将确定其作用机制和分子特征。 定义了这种酶的功能。拟议的研究具有创新性，因为它们关注的是一种新的 发现了以前没有被鉴定过的酶结构域。这项拟议的研究具有重要意义 因为它有望极大地扩展我们对Sts蛋白在调节 免疫细胞反应。由于治疗性下调Sts功能有望增加对 选择微生物病原体，我们的目标是利用这些研究的结果来开发新的抗微生物疗法 以Sts-1 PDE结构域为目标。

PROJECT SUMMARY The Sts proteins (Sts-1 and -2) negatively regulate signaling pathways within cells of the mammalian immune system. Mice lacking Sts expression (Sts-/-) are profoundly resistant to infection by clinically relevant fungal and bacterial pathogens, including Candida albicans, Francisella tularensis, and Staphylococcus aureus. Resistance is associated with rapid pathogen clearance and reduced inflammation. We recently identified a novel, functionally relevant, phosphodiesterase (PDE) enzyme activity of Sts-1. We hypothesize that this unprecedented activity plays a key role in regulating immune cell signaling pathways. To fulfill our long-term goal of developing novel therapies for infectious diseases, the objective of this proposal is to elucidate the signaling role of the Sts-1 PDE domain and identify molecular determinants of its function. Guided by strong preliminary data, we will test our hypothesis and accomplish our overall objective by pursuing the following two specific aims: 1) Elucidate the role of the Sts PDE domain in negatively regulating immune cell signaling pathways; and 2) Identify the substrate, and define the molecular determinants of function of the Sts PDE domain. In the first aim, we will utilize cell- and animal-based models to evaluate Sts-1 PDE domain function. In the second aim, we will use both a targeted, kinetics-based approach and global metabolomics to define Sts-1 PDE domain substrate breadth and specificity. In addition, we will determine the mechanism and molecular features that define the enzyme’s function. The proposed studies are innovative because they focus on a newly discovered enzyme domain that has previously not been characterized. The proposed research is significant because it is expected to substantially expand our understanding of the role of the Sts proteins in regulating immune cell responses. As therapeutic down-modulation of Sts function is expected to increase resistance to select microbial pathogens, we aim to exploit the results of these studies to develop new anti-microbial therapies that target the Sts-1 PDE domain.