C-terminal proteolysis in the Pseudomonas aeruginosa cell envelope

项目总结 铜绿假单胞菌是一种常见的人类致病菌，可导致生命- 威胁性疾病，包括急性肺炎，大多数囊性纤维化患者的长期肺部定植， 以及严重的伤口感染，特别是在住院患者和严重烧伤患者中。大多数P。 铜绿假单胞菌感染与宿主防御受损有关，这与常见的 微生物在环境中的存在，使其成为重症监护病房败血症的常见原因。这个 解决铜绿假单胞菌疾病具有挑战性，部分原因是其对抗生素的内在耐药性。 因为医院里偶尔会爆发多重耐药菌株。因此，迫切需要确定 治疗攻击的新目标。铜绿假单胞菌的细胞膜有两个C末端加工酶 或CTP(名为CTPA和PRC)，这两者都与与疾病相关的系统相关联。事实上, 许多细菌的CTP与毒力有关，但对其潜在机制知之甚少。在……里面 在铜绿假单胞菌中，CTPA对于一种被称为3型分泌系统的机器的蛋白质输出是必不可少的，这是 对急性感染最重要的毒力系统。中国已经与一个监管系统联系在一起，控制着 一种被称为藻酸盐的表面分子的产生，这与囊性疾病预后不良有关 纤维化症患者。我们现在已经发现，CTPA形成了一个具有未知外膜的复合体 脂蛋白，这有助于它的活动。这种蛋白水解物以至少一种酶为靶标，该酶可以改变 细菌细胞壁。我们推测，许多其他细菌的CTP，包括铜绿假单胞菌中的PRC，也会 与伙伴蛋白质一起作用于细胞壁修饰酶，这有助于理解这些酶是如何 蛋白水解性复合体的功能广泛而重要。因此，在这项工作中，我们将：(1)分析 脂蛋白伙伴促进CTPA依赖的蛋白分解；(2)研究CTPA底物对 细胞壁和毒力，以及它的蛋白分解如何在细菌细胞内控制；(3)扩大 这是通过表征额外的CTPA底物并测试我们的假设PRC类似的功能来实现的。 我们预测CTPs将成为一种保守的机制，细菌通过它来调节它们的一些细胞壁。 修饰酶。因此，这项工作不仅将提供对CTP如何运作的洞察，这将是 与许多病原体有关，但它也将揭示细菌如何控制其一种 临床上最重要的组成部分是细胞壁。最后，我们可以接触到的细胞包膜蛋白 这里的特征最终可能被认为是治疗药物的新靶点。

PROJECT SUMMARY The bacterium Pseudomonas aeruginosa is a common opportunistic human pathogen that causes life- threatening illnesses, including acute pneumonia, long-term lung colonization in most cystic fibrosis patients, and severe wound infections, especially in hospitalized patients and those with severe burns. Most P. aeruginosa infections are associated with compromised host defense and this, together with the common environmental occurrence of the organism, makes it a frequent cause of sepsis in the intensive care unit. The resolution of P. aeruginosa disease is challenging, in part because of its intrinsic resistance to antibiotics as well as occasional outbreaks of multi-drug-resistant strains in hospitals. Therefore, there is an urgent need to identify new targets for therapeutic attack. The cell envelope of P. aeruginosa has two C-terminal processing proteases or CTPs (named CtpA and Prc), both of which have been linked to systems associated with disease. In fact, many bacterial CTPs have been linked to virulence but very little is known about the underlying mechanisms. In P. aeruginosa, CtpA is essential for protein export by a machine known as a type 3 secretion system, one of the most important virulence systems for acute infections. Prc has been linked to a regulatory system that controls the production of a surface molecule known as alginate, which is associated with a poor prognosis in cystic fibrosis patients. We have now discovered that CtpA forms a complex with an uncharacterized outer membrane lipoprotein, which facilitates its activity. This proteolytic complex targets at least one enzyme that modifies the bacterial cell wall. We hypothesize that many other bacterial CTPs, including Prc in P. aeruginosa, will also work with partner proteins to target cell wall modifying enzymes, which makes an understanding of how these proteolytic complexes function broadly significant. Therefore, in this work we will: (1) Analyze how the lipoprotein partner facilitates CtpA-dependent proteolysis; (2), Investigate the impact of a CtpA substrate on the cell wall and virulence, and how its proteolysis is controlled within the bacterial cell; (3) Broaden the impact of this work by characterizing additional CtpA substrates and testing our hypothesis that Prc functions similarly. We predict that CTPs will emerge as a conserved mechanism by which bacteria regulate some of their cell wall modifying enzymes. Therefore, not only will this work provide insight into how CTPs function, which will be of relevance to many pathogens, but it will also shed light on how bacteria control the metabolism of one of their most clinically important components, the cell wall. Finally, the accessible cell envelope proteins that we characterize here could eventually be considered as new targets for therapeutic drugs.