Functional Analysis of the T. gondii AMA1 Cytosolic Tail

刚地弓形虫是一种广泛分布的原生动物寄生虫，它会导致身体虚弱，有时甚至是生命的丧失。 妊娠期间和免疫功能低下的个体，包括艾滋病患者的威胁性疾病。 弓形虫病是美国第二大常见的食源性疾病死亡原因， 经济每年数十亿美元。T.弓形虫也是一种有价值的顶复门动物实验模型 寄生虫，包括那些导致疟疾和隐孢子虫病。宿主细胞的侵入对于 顶膜抗原1（AMA 1）是寄生虫的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。关于细胞外的 在侵袭过程中，AMA 1的结构域与宿主细胞表面上的配体（RON 2）相互作用，但令人惊讶的是， 已知其位于寄生虫胞质溶胶中的短的C-末端尾部的功能。中央 本项目假设T.弓形虫AMA 1（TgAMA 1）在侵袭相关的 信号通路，通过与其他寄生虫蛋白质的相互作用。 该项目的目标是： (a)确定TgAMA 1胞质尾部特定突变的表型结果， 胞质尾区在侵入的哪个步骤起作用以及涉及的特定残基; (b)鉴定和确定与TgAMA 1胞质尾相互作用的蛋白质的生物学功能， 确定破坏入侵的尾突变是否也影响特定蛋白质的结合;以及 (c)确定TgAMA 1与TgRON 2的结合是否触发由TgAMA 1介导的细胞内信号传导。 TgAMA 1胞质尾部，导致寄生虫磷酸化蛋白质组的侵袭相关变化。 这些研究解决了我们对AMA 1在侵袭中所起作用的理解中的一个重大空白。 宿主细胞的寄生虫。对AMA 1功能的更全面理解将产生新的 预防或控制这一重要人群所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.