Microsporidia: invasion apparatus

摘要微孢子虫是一种重要的真菌寄生虫， 超过150年。他们对所有动物的剥削都是引人注目的， 感染到壮观的大规模感染，造成广泛的损害，往往导致宿主死亡。 小孢子虫是艾滋病患者的机会致病菌，最常见的是引起腹泻， 脑炎、肌炎或结膜炎。微孢子虫也可以引起其他免疫系统的感染。 受损宿主，如接受过器官移植或免疫缺陷的患者 调节疗法。它们还能够感染免疫活性宿主， 角膜结膜炎或腹泻。这些病原微生物被归为NIH B类优先级 病原体和EPA病原体的利益，因为它们通过食物和水源传播。在 除了是人类病原体外，微孢子虫病对农业具有重大的经济影响（通过影响 昆虫和养蚕）、水产养殖和动物（食用、家养和野生动物）。微孢子虫产生 孢子具有独特的侵入机制，即极管，这是最复杂的单细胞 在生物学世界中是已知的。极管与宿主细胞相互作用的机制 入侵的时间仍然未知。在我的实验室小组中，一个长期的研究项目集中在 了解入侵机制和极管的结构生物学和组成。我们 已经开发了这种结构的纯化技术，鉴定了极管蛋白（PTP）， 它们的翻译后修饰以及这些蛋白质如何相互作用。但是，我们的研究已经开始了 以确定这些蛋白质在极管的结构生物学中的功能作用， 入侵然而，这种结构中的蛋白质的完整补充以及这些蛋白质之间的相互作用， 在入侵过程中的成分仍有待确定，在其他微生物的入侵研究提供了 了解发病机制和新的治疗方法来管理的关键数据 感染.我们已经证明，主要的极管蛋白是O-乙酰基化的，这是一种翻译后修饰。 参与侵入的修饰，抑制甘露糖的结合可以限制感染， 针对极性管蛋白1（polar tube protein 1，PTP 1）的抗体可以阻断侵袭，表明靶向侵袭细胞器 是一种限制感染的方法拟议的研究项目将采用蛋白质组学， 免疫学和超微结构研究，以表征极管及其蛋白质相互作用组，以更好地 明确和研究入侵机制。我们还将评估一个新发现的极地生物 管蛋白（PTP 4）结合宿主细胞成分，并使用PTP 4的抗体作为标记物来鉴定 发生侵袭的细胞区域。这将有助于详细的相关微观分析 这些病原体入侵的机制。此外，电子显微镜技术将是 用于提供对构成极管的蛋白质的三维结构的深入了解 提供了关于这种入侵细胞器组织的基本问题的关键信息 这些都是传统显微镜无法分辨的。研究的组成，形成和 这种细胞器在萌发和入侵过程中的功能应该为发育提供基础。 控制这些重要的寄生原生生物的新策略。

ABSTRACT Microsporidia are remarkable parasites related to the Fungi that have been studied for more than 150 years. They are remarkable in their exploitation of all animals ranging from cryptic, benign infections to spectacular, massive infections that cause extensive damage and often death of the host. Microsporidai are opportunistic pathogens in patients with AIDS most commontly causing diarrhea, encephalitis, myositis, or conjunctivitis. Microsporidia can also cause infections in other immune compromised hosts, such as patients who have undergone organ transplantation or those on immune modulating therapies. They are also capable of infecting immune competent hosts most commonly causing keratoconjunctivitis or diarrhea. These pathogenic organisms are classified as NIH category B priority pathogens and EPA pathogens of interest as they are transmitted by both food and water sources. In addition to being human pathogens, microsporidiosis has major economic impacts on agriculture (via effects on insects and sericulture), aquaculture and animals (food, domestic and wildlife). Microsporidia produce spores with a unique invasion mechanism, the polar tube, that is one of the most complex single celled forms known in the biological world. The mechanism by which the polar tube interacts with the host cell during invasion is still unknown. A long standing research program in my laboratory group is focused on understanding the mechanism of invasion and the structural biology and composition of the polar tube. We have developed techniques for the purificaiton of this structure, identified polar tube proteins (PTPs) and their post translational modifications and how these proteins interact. Futhermore, our studies have begun to define the functional roles of these proteins in the structural biology of the polar tube and the process of invasion. However, the full complement of proteins in this structure and the interactions of these components during invasion remain to be determined, In other microbes studies on invasion have provided key data for understanding pathogenesis and for new therapeutic approaches to the management of infections. We have demonstrated that the major polar tube protein is O-manosylated, a post translational modification that is involved in invasion, that inhibiting binding of manose can limit infection, and that antibody to polar tube protein 1 (PTP1) can block invasion demonstrate that targeting the invasion organelle is a way to limit infection. The proposed research project will employ a combination of proteomic, immunologic and ultrastructural studies to characterize the polar tube and its protein interactome to better define and study the mechanism of invasion. We will also evaluate the ability of a newly identified polar tube protein (PTP4) to bind to host cell components and use antibody to PTP4 as a marker to identify the area of the cell at which invasion is occurring. This will facilitate a detailed correlated microscopic analysis of the mechanism of invasion by these pathogens. Furthermore, electron microscopic techniques will be employed to provide insight into the three dimenstional structure of the proteins making up the polar tube providng critical information on fundamental questions concerning the organization of this invasion organelle that have not been able to be resolved by traditional microscopy. Studies of the composition, formation and function of this organelle during germination and invasion should provide a basis for the development of new strategies for control of these important parasitic protists.