Post-translational regulation of type VI secretion in Pseudomonas aeruginosa

性状（由申请方提供）：细菌的毒力与其释放分泌因子的能力密切相关。因此，致病性革兰氏阴性菌（I-VI型）中存在许多进化上不同的蛋白质易位途径。VI型分泌（T6 S）是这些途径中最新描述的，是许多病原菌毒力的重要贡献者。该提案的PI Joseph Mougous博士首先在铜绿假单胞菌中表征了该分泌系统。这项工作产生了对分泌系统的基本生化和结构见解;此外，它提供了证据表明铜绿假单胞菌的T6 S系统（T6 SS）对于这种生物体在囊性纤维化患者中引起的破坏性慢性感染很重要。该提案的重点以及Mougous博士实验室的主要研究重点是了解严格调节铜绿假单胞菌T6 SS活性的调节途径。这一途径，这是真核生物的信号，是由跨膜丝氨酸-苏氨酸激酶的二聚化启动。这引发了一系列“触发”分泌系统的事件，导致底物移位。虽然Mougous博士先前的工作已经揭示了这一途径的一些机制细节，但许多关键问题仍然没有答案。所提出的实验试图回答这些机制问题，并利用这种新的调节模式来识别分泌系统的底物-该领域目前的障碍。许多对人类健康和生物防御具有重要意义的病原体都需要T6 S来进行毒力，并利用这一途径来调节其活性;因此，拟议研究产生的结果将具有广泛的影响，并可能导致新的治疗策略的开发。公共卫生相关性：病原菌利用蛋白质分泌引起疾病。本提案的目的是研究一种类型的蛋白质分泌，VI型分泌（T6 S），是如何调节的机会人类病原体铜绿假单胞菌。拟议的研究还试图了解T6 S释放的哪些因素有助于其在慢性铜绿假单胞菌感染中的作用。

DESCRIPTION (provided by applicant): The virulence of a bacterium is closely linked to its ability to release secreted factors. It follows that many evolutionarily distinct pathways exist for the translocation of proteins in pathogenic Gram-negative bacteria (types I-VI). Type VI secretion (T6S), the most recently described of these pathways, is an important contributor to the virulence of many pathogenic bacteria. The PI of this proposal, Dr. Joseph Mougous, first characterized this secretion system in Pseudomonas aeruginosa. This work produced fundamental biochemical and structural insights into the secretion system; furthermore, it provided evidence that the T6S system (T6SS) of P. aeruginosa is important for the devastating chronic infections this organism causes in cystic fibrosis patients. The focus of this proposal, and the major research emphasis of Dr. Mougous' laboratory, is to understand the regulatory pathway that tightly modulates the activity of the P. aeruginosa T6SS. This pathway, which is reminiscent of eukaryotic signaling, is initiated by dimerization of a transmembrane serine-threonine kinase. This provokes a series of events that "triggers" the secretion system, leading to substrate translocation. Although prior work by Dr. Mougous has revealed some of the mechanistic details of this pathway, many key questions remain unanswered. The proposed experiments seek to answer these mechanistic questions, and also to utilize this novel mode of regulation for the purpose of identifying substrates of the secretion system - a current impediment to the field. Many pathogens of significance to human health and biodefense require T6S for virulence and use this pathway to regulate its activity; therefore, findings generated by the proposed research will have broad implications and could lead to the development of new therapeutic strategies. PUBLIC HEALTH RELEVANCE: Pathogenic bacteria utilize protein secretion to cause disease. The aims of this proposal investigate how one type of protein secretion, type VI secretion (T6S), is regulated in the opportunistic human pathogen Pseudomonas aeruginosa. The proposed research also seeks to understand what factors released by T6S contribute to its role in chronic P. aeruginosa infections.