MODULATION OF HOST SIGNALING FUNCTIONS BY YERSINIA YOPS

描述（改编自申请人的摘要）： 耶尔森菌（Y. pestis，Y. enterocolitica和Y.假结核） 导致一系列疾病，包括腹泻，肠系膜 淋巴结炎和黑死病这些细菌侵入并定居在 人类和各种动物宿主的淋巴器官。定殖 宿主需要质粒编码的接触依赖性 III型分泌系统。这种III型系统将一组有毒的 被称为Yops的蛋白质进入宿主细胞。野猿会损害正常的宿主细胞 信号功能，导致抑制吞噬作用，抑制 细胞因子合成和诱导细胞凋亡。长期目标是 格兰特是为了了解Yops如何调节宿主细胞信号功能。的 研究人员将把他们的研究主要集中在YopH，一种蛋白质酪氨酸 磷酸酶，抑制吞噬作用，和YopJ，一种蛋白质， 细胞因子合成并诱导细胞凋亡。第一个具体目标是 对YopH中的氨基末端结构域进行了结构/功能分析， 介导易位和底物识别。结合生物物理学 而遗传学方法将被用来实现这一目标。第二特定 目的是研究YopH在宿主体内识别底物的机制 细胞动物和培养细胞感染试验将用于研究 基因改变的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， 阐明其作用机理。YopJ的突变形式不能结合靶标 将产生蛋白质并分析其在动物中的生物活性， 培养细胞感染测定。其他Yop人调节 宿主细胞中促分裂原活化蛋白激酶的活性也将被 探讨了由于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提供了一个非常 研究病原体干扰宿主信号功能的强大系统， 这些研究将有助于制定新的战略， 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.