Functional Analysis of the T. gondii AMA1 Cytosolic Tail

弓形虫是一种分布广泛的原生动物寄生虫，会使人虚弱，有时还会导致生命- 在怀孕期间和免疫功能受损的个人，包括艾滋病患者中，存在威胁疾病的风险。 在美国，弓形虫病是食源性疾病导致的第二大常见死亡原因， 每年节省数十亿美元。弓形虫也是研究相关复合体的有价值的实验模型。 寄生虫，包括那些导致疟疾和隐孢子虫病的寄生虫。宿主细胞的入侵对于 寄生虫的生活史，顶膜抗原1(AMA1)是一种高度保守的跨膜蛋白 在入侵中起重要作用的寄生虫表面。很多人都知道细胞外如何 AMA1的结构域在入侵过程中与宿主细胞表面(RON2)上的配体相互作用，但令人惊讶的是很少 已知其位于寄生虫胞质中的短尾C末端的功能。中环 本项目的假设是弓形虫AMA1的胞液尾巴(TgAMA1)在侵袭相关的 信号通路，通过与其他寄生虫蛋白的相互作用。 该项目的目标是： (A)确定TgAMA1胞浆尾部特定突变的表型后果，确定 在什么阶段(S)入侵，胞浆尾部功能和涉及的特定残基； (B)鉴定和确定与TgAMA1胞浆尾巴相互作用的蛋白质的生物学功能， 确定破坏入侵的尾部突变是否也影响特定蛋白质的结合；以及 (C)确定TgAMA1与TgRON2的结合是否触发了由TgAMA1和TgRON2介导的细胞内信号传递 TgAMA1胞浆尾巴，导致寄生虫磷蛋白质组的入侵相关变化。 这些研究解决了我们对AMA1在入侵的过程中扮演的角色的理解上的一个重大差距。 顶端复合体寄生虫寄生的宿主细胞。对AMA1功能的更全面理解将产生新的 预防或控制由这一重要人类群体造成的毁灭性疾病的方法 病原体。

Toxoplasma gondii is a widespread protozoan parasite that causes debilitating and sometimes life- threatening disease during pregnancy and in immunocompromised individuals, including those with AIDS. Toxoplasmosis is the second most common cause of death by foodborne illness in the USA and costs the economy billions of dollars annually. T. gondii is also a valuable experimental model for related apicomplexan parasites, including those that cause malaria and cryptosporidiosis. Host cell invasion is essential to the parasite's life cycle, and apical membrane antigen1 (AMA1) is a highly conserved transmembrane protein on the parasite surface that plays an important role in invasion. Much is known about how the extracellular domain of AMA1 interacts with its ligand on the host cell surface (RON2) during invasion, but surprisingly little is known about the function of its short, C-terminal tail, which is located in the parasite cytosol. The central hypothesis of this project is that the cytosolic tail of T. gondii AMA1 (TgAMA1) functions in invasion-related signaling pathways, through interaction with other parasite proteins. The Aims of the project are to: (a) Determine the phenotypic consequences of specific mutations in the TgAMA1 cytosolic tail, establishing at what step(s) in invasion the cytosolic tail functions and the specific residues involved; (b) Identify and determine the biological function of proteins that interact with the TgAMA1 cytosolic tail, establishing whether tail mutations that disrupt invasion also affect the binding of specific proteins; and (c) Determine whether the binding of TgAMA1 to TgRON2 triggers intracellular signaling mediated by the TgAMA1 cytosolic tail, resulting in invasion-related changes to the parasite phosphoproteome. These studies address a significant gap in our understanding of the role that AMA1 plays in the invasion of host cells by apicomplexan parasites. A more complete understanding of AMA1 function will generate new approaches to preventing or controlling the devastating diseases caused by this important group of human pathogens.