Role of Yersinia pestis Ail in Yop delivery and plague

描述（由申请人提供）：革兰氏阴性菌的有效三型分泌（T3 S）需要粘附至靶宿主细胞。我们最近已经确定鼠疫耶尔森氏菌粘附素Ail通过结合宿主纤连蛋白促进耶尔森氏菌外蛋白（Yops）的T3 S。鼠疫感染需要Yop传递，缺乏Yop的突变体完全无毒。一个？所有突变体在体外具有差的Yop递送，并且在体内减弱（LD 50增加>3000倍）。因此，Ail似乎是用于体内Yop递送的突出粘附素。这使得Ail成为Y的重要潜在目标。鼠疫疫苗开发和抗鼠疫疗法。我们假设Ail与纤连蛋白一起与宿主细胞相互作用以允许有效的Yop递送，这可能是通过刺激Yop递送所需的受体启动的细胞信号传导。我们进一步假设Fn作为Ail表达细菌和宿主细胞上的21种整合素（Fn的受体）之间的桥梁。? 1整合素信号传导最近已被证明对于由密切相关的病原体Y.假结核在这项建议中，我们将定义的区域AIL与Fn相互作用，并解决的影响AIL绑定到Fn和随后的参与？1整合素。通过了解Yop交付过程中的关键步骤，鼠疫，我们将显着扩大我们的知识，特别是在Yop交付和T3 S一般的粘附作用。这些研究将广泛适用于利用T3 S机制进行毒素递送的其他细菌病原体。此外，通过定义Y.鼠疫和宿主细胞，我们可以确定可用于治疗鼠疫的治疗靶点，鼠疫是一种快速致命的疾病和生物恐怖主义威胁。 这项建议的目的是： 目的1：确定宿主细胞结合和Yop递送所需的Ail的残基 目的2：研究Ail与宿主细胞纤连蛋白的结合以及21种整合素在Ail介导的Yop传递中的作用 公共卫生相关性：鼠疫耶尔森氏菌引起迅速致命的传染病鼠疫，使Y。鼠疫是生物恐怖主义威胁本项目旨在加深我们对Y染色体相互作用的理解。鼠疫菌表面蛋白Ail与宿主细胞的相互作用。这种关键的相互作用是鼠疫毒力所必需的，表征这种相互作用可能会导致抗鼠疫疗法和/或有效的鼠疫疫苗的开发。

DESCRIPTION (provided by applicant): Efficient Type Three Secretion (T3S) by Gram-negative bacteria requires adhesion to the targeted host cell. We have recently determined that the Yersinia pestis adhesin Ail facilitates T3S of Yersinia outer proteins (Yops) via binding to host fibronectin. Yop delivery is required for plague infection and mutants that lack Yops are completely avirulent. A ?ail mutant has poor Yop delivery in vitro and is attenuated in vivo (>3000-fold increase in LD50). Thus, Ail appears to be a prominent adhesin for Yop delivery in vivo. This makes Ail an important potential target for Y. pestis vaccine development and anti-plague therapies. We hypothesize that Ail in conjunction with fibronectin interacts with host cells to allow efficient Yop delivery, possibly by stimulating receptor-initiated cell signaling required for Yop delivery. We further hypothesize that Fn acts as a bridge between Ail-expressing bacteria and 21 integrins on host cells (receptors for Fn). ?1 integrin signaling has recently been shown to be important for invasin-mediated Yop delivery by the closely related pathogen, Y. pseudotuberculosis. In this proposal, we will define the regions of Ail that interact with Fn and address the effects of Ail binding to Fn and subsequent engagement of ?1 integrins. By understanding this critical step in the Yop delivery process by a key adhesin of Y. pestis, we will significantly expand our knowledge of the role of adhesion in Yop delivery in particular and T3S in general. These studies will be broadly applicable to other bacterial pathogens that utilize a T3S mechanism for toxin delivery. Furthermore by defining a crucial interaction mechanism between Y. pestis and host cells, we may identify targets for therapeutics that can be used to treat plague, a rapidly fatal disease and bioterrorism threat. The Aims of this proposal are: Aim 1: Determine the residues of Ail required for host cell binding and Yop delivery Aim 2: Characterize Ail binding to host cell fibronectin and the role of 21 integrins in Ail-mediated Yop delivery PUBLIC HEALTH RELEVANCE: Yersinia pestis causes the rapidly fatal infectious disease plague, making Y. pestis a bioterrorism threat. This project is aimed at furthering our understanding of the interaction of the Y. pestis surface protein Ail with host cells. This critical interaction is required for plague virulence and characterizing this interaction may lead to development of anti-plague therapeutics and/or an effective plague vaccine.