How Regulated Proteolysis Controls Bacterial Virulence

项目总结 所有病原体都需要蛋白质才能致病。蛋白质丰度反映了一种微妙的平衡 在合成和降解之间，对致病机制和抗生素耐受性至关重要。蛋白 必须严格控制降解，因为它的影响是不可逆转的。我们的目标是确定 包括人类胃肠炎和小鼠伤寒在内的相关细菌物种如何 肠沙门氏菌作为鼠伤寒沙门氏菌的血清型，将蛋白分解作为一种基本的毒力策略。 我们将调查主要的毒力调节因子Phop是如何控制病毒的丰度、活性或 五种ATP依赖的蛋白水解酶：Lon、HslUV、ClpAP、ClpXP和FtsH的特异性。我们会 研究Phop拮抗剂EIIANtr是如何以依赖于Phop和Lon的方式被蛋白质降解的 确定Phop和EIIANtr的蛋白分解在表达动力学中所起的作用 细菌在巨噬细胞内时的毒力基因。我们将揭示蛋白质和行为 由鲜为人知的毒力促进酶HslUV控制；关键测试其作用 基因沉默剂H-NS的蛋白分解在外源基因的表达中发挥作用；并解决 蛋白酶适配器防止蛋白质在感染过程中降解的机制(S)。我们会 鉴定控制毒力蛋白CSPI和IRAP表达的5‘端信号 MRNAs和确定毒力蛋白mGtB的结构域(S)在很低的水平上调节生长 Mg2+与SLc11a1+/+巨噬细胞存活拟议的研究计划需要一个 全面的方法，包括技术和概念创新，以揭示重大、 细菌生理学和致病机理的广泛应用原理及新疗法 克服抗生素耐药性的干预措施。

PROJECT SUMMARY All pathogens require proteins to cause disease. Protein abundance reflects a delicate balance between synthesis and degradation critical for pathogenesis and antibiotic tolerance. Protein degradation must be tightly controlled because its effects are irreversible. We aim to determine how related bacterial species, including the human gastroenteritis- and murine typhoid-causing Salmonella enterica serovar Typhimurium, deploy proteolysis as an essential virulence strategy. We will investigate how the master virulence regulator PhoP controls the abundance, activity, or specificity of all five ATP-dependent proteases: Lon, HslUV, ClpAP, ClpXP, and FtsH. We will examine how the PhoP antagonist EIIANtr is proteolyzed in a phoP- and lon-dependent manner and identify the role that proteolysis of PhoP and EIIANtr plays in the expression kinetics of virulence genes when bacteria are inside macrophages. We will uncover proteins and behaviors controlled by the poorly understood virulence-promoting protease HslUV; critically test the role that proteolysis of gene silencer H-NS plays in expression of foreign genes; and solve the mechanism(s) by which protease adaptors prevent protein degradation during infection. We will identify the signals governing expression of virulence proteins CspI and IraP via their 5' leader mRNAs and define the domain(s) of the virulence protein MgtB mediating growth in very low Mg2+ and survival in Slc11a1+/+ macrophages. The proposed research program takes a comprehensive approach, including technical and conceptual innovations, to reveal significant, broadly applicable principles in bacterial physiology and pathogenesis and new therapeutic interventions that overcome antibiotic resistance.