Molecular mechanism of general stress signaling in Brucella abortus

描述（由申请人提供）：本研究项目的目标是对选择性病原体流产布鲁氏菌中的一般应激反应（GSR）信号传导系统进行机制性理解。我们的初步数据表明，这个信号系统控制环境压力适应和慢性感染的哺乳动物感染模型。B。流产GSR信号传导部分由PhyR蛋白控制，PhyR蛋白是一种保守的适应环境应激的调节因子，在变形菌进化枝中广泛保守。PhyR含有一个氨基端ECF样结构域和一个羧基端TCS受体结构域。磷酸化激活PhyR作为一种抗-抗-<$因子，并释放经典的ECF <$因子<$E1，在应激期间直接调节基因表达。我们对PhyR、E1和GSR信号系统的其他组成部分的多学科研究将定义对人类健康、农业和生物防御有重要意义的病原体中一般应激信号的机制基础。此外，本文提出的实验有可能为布鲁氏菌病等变形菌疾病提供新的治疗方法。如上所述，该提案是高度多学科的，跨越遗传学、生物化学、分子生物物理学、细胞生物学和整个动物感染研究。我将与三名经验丰富的博士后研究员组成的团队进行这些研究，他们都具有在芝加哥大学霍华德泰勒里基茨地区生物遏制实验室研究这种BSL 3选择剂的专业知识。本课题的具体目标是：1）明确组氨酸激酶LovhK作为GSR应激传感器的作用，并表征LovhK检测应激信号的分子基础。2)定义激活B的信号。体外和哺乳动物感染模型中的一般应激反应。3)阐明GSR激活的结构机制。

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.