MODULATION OF HOST SIGNALING FUNCTIONS BY YERSINIA YOPS

描述(改编自申请者摘要)：人类致病 耶尔森氏菌(Yersinia spp.)(鼠疫耶尔森氏菌、小肠结肠炎耶尔森氏菌和假结核耶尔森氏菌) 对一系列疾病负责，包括腹泻、肠系膜 淋巴结炎和腺鼠疫。这些细菌入侵并定居在 人类和各种动物宿主的淋巴器官。一个殖民地的殖民 耶尔森氏菌的宿主需要一种接触依赖的质粒编码的功能 III型分泌系统。这种III型系统转移了一组有毒的 被称为YOPs的蛋白质进入宿主细胞。YOP会损害正常的宿主细胞 信号功能，导致抑制吞噬，抑制 细胞因子的合成和诱导细胞凋亡。这样做的长期目标是 格兰特的任务是了解YOP如何调节宿主细胞的信号功能。这个 调查人员将主要研究YopH，一种蛋白质酪氨酸 抑制吞噬作用的磷酸酶，以及阻止吞噬的蛋白质YopJ 细胞因子的合成和诱导细胞凋亡。第一个具体目标是进行 对YopH中一个氨基末端结构域进行了结构/功能分析 介导转位和底物识别。一种生物物理的组合 而遗传方法将被用来实现这一目标。第二个具体问题 目的是研究YopH在宿主体内识别底物的机制 细胞。将使用动物和培养细胞感染试验来研究 转基因YopH蛋白在体内的行为。第三个具体目标 是分析YopJ与宿主靶蛋白的相互作用，并 阐明其作用机制。YopJ的突变形式无法结合靶标 将产生蛋白质并分析其在动物和 培养细胞感染检测。其他YOP调制的可能性 宿主细胞中丝裂原活化蛋白激酶的活性也将 探索过了。AS III型分泌途径是重要的毒力决定因素 在大量的细菌病原体中，YOPs提供了一种极其 研究病原体干扰宿主信号功能的强大系统， 这些研究将有助于开发新的战略，以打击各种 传染病。

DESCRIPTION (Adapted from the Applicant's Abstract): The human-pathogenic Yersinia spp. (Y. pestis, Y. enterocolitica, and Y. pseudotuberculosis) are responsible for a range of diseases including diarrhea, mesenteric lymphadenitis, and bubonic plague. These bacteria invade into and colonize the lymphatic organs of humans and a variety of animal hosts. Colonization of a host by Yersinia requires the function of a plasmid-encoded contact-dependent type III secretion system. This type III system translocates a set of toxic proteins known as Yops into host cells. The Yops impair normal host cell signaling functions, resulting in inhibition of phagocytosis, suppression of cytokine synthesis, and induction of apoptosis. The long-term goal of this grant is to understand how Yops modulate host cell signaling functions. The investigators will focus their studies primarily on YopH, a protein tyrosine phosphatase that inhibits phagocytosis, and YopJ, a protein that prevents cytokine synthesis and induces apoptosis. The first specific aim is to carry out a structure/function analysis of an amino-terminal domain in YopH that mediates translocation and substrate recognition. A combination of biophysical and genetic approaches will be used to achieve this goal. The second specific aim is to examine the mechanism of substrate recognition by YopH inside host cells. Animal and cultured cell infection assays will be used to study the behavior of genetically-altered YopH proteins in vivo. The third specific aim is to analyze the interaction of YopJ with host target proteins and to elucidate its mechanism action. Mutant forms of YopJ unable to bind target proteins will be generated and analyzed for biological activity in animal and cultured cell infection assays. The possibility that other Yops modulate the activities of mitogen-activated protein kinases in host cells will also be explored. As type III secretion pathways are important virulence determinants in a large number of bacterial pathogens, and the Yops provide an extremely powerful system to study pathogen interference with host signaling functions, these studies will aid the development of new strategies to combat a variety infectious diseases.