Molecular mechanism of general stress signaling in Brucella abortus

描述(由申请人提供)：本研究计划的目标是从机理上理解选择性病原体布鲁氏菌中的一般应激反应(GSR)信号系统。我们的初步数据表明，在哺乳动物感染模型中，该信号系统控制环境应激适应和慢性感染。B.Abortus的GSR信号在一定程度上受PHYR蛋白的控制，PHYR蛋白是一种保守的适应环境胁迫的调节因子，在蛋白细菌分支中广泛保守。PHYR含有一个氨基末端的ECF样结构域和一个羧基末端的TCS受体结构域。磷酸化激活PHYR作为一种抗因子，并释放经典的ECF因子？E1，在应激过程中直接调节基因的表达。我们对PHYR、？E1和GSR信号系统的其他组件的多学科研究将确定一般应激信号在病原体中的机制基础，这些信号对人类健康、农业和生物防御具有重要意义。此外，这里提出的实验有可能为布鲁氏菌病等蛋白细菌疾病的新治疗提供信息。如上所述，这项建议是高度多学科的，横跨遗传学、生物化学、分子生物物理学、细胞生物学和全动物感染研究。我将与一个由三名经验丰富的博士后研究员组成的团队进行这些研究，他们都拥有芝加哥大学霍华德·泰勒·里基茨区域生物遏制实验室这种BSL3选择药物的专业知识。本项目的具体目标是：1)明确传感器组氨酸激酶LovhK作为GSR应激感受器的作用，并表征LovhK检测应激信号的分子基础。2)确定在体外和哺乳动物感染模型中激活流产杆菌一般应激反应的信号。3)阐明了GSR活化的结构机制。

DESCRIPTION (provided by applicant): The goal of this research program is to develop a mechanistic understanding of the general stress response (GSR) signaling system in the select agent pathogen, Brucella abortus. Our preliminary data demonstrate that this signaling system controls environmental stress adaptation and chronic infection in a mammalian infection model. B. abortus GSR signaling is controlled in part by the PhyR protein, a conserved regulator of adaptation to environmental stress that is broadly conserved in the ¿-proteobacterial clade. PhyR contains an amino terminal ECF ¿-like domain and a carboxy-terminal TCS receiver domain. Phosphorylation activates PhyR as an anti-anti-¿ factor and releases the classical ECF ¿ factor, ¿E1 to directly regulate gene expression during stress. Our multi-disciplinary investigation of PhyR, ¿E1 and other components of the GSR signaling system will define the mechanistic underpinnings of general stress signaling in a pathogen of significant human health, agricultural, and biodefense import. Moreover, the experiments proposed herein have the potential to inform new treatments for ¿-proteobacterial disease such as brucellosis. As mentioned above, this proposal is highly multi-disciplinary, spanning genetics, biochemistry, molecular biophysics, cell biology, and whole-animal infection studies. I will conduct these studies with a team of three experienced postdoctoral fellows, all of whom have expertise working on this BSL3 select agent in containment at the University of Chicago Howard Taylor Ricketts Regional Biocontainment Laboratory. The specific aims of this project are: 1) Define the role of the sensor histidine kinase, LovhK, as a GSR stress sensor, and characterize the molecular basis of stress signal detection by LovhK. 2) Define signals that activate the B. abortus general stress response in vitro and in a mammalian infection model. 3) Elucidate the structural mechanism of GSR activation.