Activity of Pseudomonas Type III Toxins

了解宿主和寄生虫之间的动态相互作用为防止对寄生虫的损害提供了机会。 宿主组织和限制寄生复制。假单胞菌III型系统在急性炎症中起重要作用。 感染，并可能在慢性感染的建立中发挥最初的作用。四种效应物或毒素， ExoS、ExoT、ExoY和ExoU通过分泌装置直接注射到真核细胞中， 共享重要属性。每个效应子是一种酶，并且每个酶需要真核辅因子或 最大活性的活化剂。催化活性确保快速中毒和改变细胞生理 以利于细菌在宿主环境中的复制和存活。细胞关键成分失活 包括对吞噬作用和细菌破坏重要的细胞骨架成分的防御（ExoS， ExoT、ExoY）、细胞间相互作用（ExoY）、细胞信号传导途径（ExoS、ExoT、ExoY）和膜 完整性（ExoU）改变先天免疫反应，不仅有助于建立感染， 允许表达其他毒力因子以促进向其他组织的传播。当前应用程序 建立在我们对ExoU（磷脂酶）作用机制的发现和最近的数据， 超氧化物歧化酶（SOD）作为ExoU的辅因子。重要的是，哺乳动物SOD定位于 细胞内和细胞外区室。我们假设，exoU的辅因子的本地化- 磷脂酶活性可以控制酶的生物活性，并促进定殖或 在细菌入侵的某些阶段传播。了解酶促反应的关键元素 活性一起工作，改变蛋白质将允许合理的抑制剂，中断 严重铜绿假单胞菌感染的病理后果。重要的是，这些研究可以揭示 关于辅因子、细菌酶及其 哺乳动物同源物（JPLA 2、cPLA 2和patatin）。最后，脂质代谢和花生四烯酸的产生 酸影响免疫功能和细胞代谢的调节。调查生物学 ExoU中毒的后果可能导致关于对P的炎症反应的新见解。 铜绿假单胞菌及其产品，并可能导致治疗组合的设计，可以帮助 重症患者或处于慢性感染早期的患者。

Understanding the dynamic interaction between host and parasite offers opportunities to prevent damage to host tissues and limit parasitic replication. The Pseudomonas type III system plays an important role in acute infections and may play an initial role in the establishment of chronic infections. Four effectors or toxins, ExoS, ExoT, ExoY and ExoU, are directly injected into eukaryotic cells by the secretion apparatus and all share important properties. Each effector is an enzyme and each enzyme requires a eukaryotic cofactor or activator for maximal activity. Catalytic activity ensures rapid intoxication and alteration of cellular physiology to benefit bacterial replication and survival in a host environment. Inactivation of key elements of cellular defenses that include cytoskeletal components important for phagocytosis and bacterial destruction (ExoS, ExoT, ExoY), intercellular interactions (ExoY), cell signaling pathways (ExoS, ExoT, ExoY) and membrane integrity (ExoU) alter the innate immune responses and can aid not only in establishing the infection but also allow expression of other virulence factors to promote dissemination to other tissues. The current application builds upon our discovery of the mechanism of action of ExoU (phospholipase) and recent data implicating superoxide dismutase (SOD) as a cofactor for ExoU. Importantly, mammalian SODs are localized to both intracellular and extracellular compartments. We postulate that the localization of the cofactor for ExoU- phospholipase activity may govern the biologic activities of the enzyme and promote either colonization or dissemination at certain stages of bacterial invasion. Understanding how the elements critical to enzymatic activity work together to alter the protein will allow rational development of inhibitors that interrupt the pathological consequences of serious P. aeruginosa infections. Importantly, these studies could reveal evolutionary insights regarding the relationships between the cofactors, bacterial enzymes and their mammalian homologs (JPLA2, cPLA2 and patatin). Finally lipid metabolism and the production of arachidonic acids effect immune function and the regulation of cellular metabolism. Investigating the biological consequences of ExoU intoxication may lead to new insights regarding the inflammatory response to P. aeruginosa and its products and may result in the design of a combination of therapeutics that could aid individuals who are critically ill or in the early stages of chronic infection.