Characterizing Plasmodium proteins at the host-pathogen vacuolar interface during parasite development in the liver

对于膜结合的细胞内寄生虫，包围病原体的液泡是与宿主细胞通讯的门户。因此，这种膜在营养获取、保护宿主防御方面发挥作用，并且在许多情况下必须在感染期间扩张以适应发育中的寄生虫。我们相信，通过研究两种疟原虫蛋白质，UIS 4和以前未描述的Lex3，它们存在于疟原虫寄生虫空泡（PV）及其扩展的膜网络（TVN）中，我们可以更好地了解这个隔室如何执行这些功能。我们选择这些蛋白质是因为它们的差异表达模式：UIS4在感染后早期表达，并且仅在肝细胞感染中表达，而Lex3在肝细胞感染后期和血液感染期间表达。因此，与这些蛋白质，我们可以比较膜动力学和宿主细胞的影响，这些动力学在所有哺乳动物感染阶段。最初，我们将精确地可视化和表征受感染细胞中的Lex3和UIS4阳性结构。然后，我们将评估宿主细胞骨架元素和膜转运途径对PV和TVN动力学的贡献。最后，我们将通过确定UIS4和Lex3的宿主蛋白相互作用伙伴来寻找对疟原虫细胞内生长重要的宿主因子。通过这些研究，我们将更好地表征含疟原虫的液泡，并提高我们对疟原虫细胞内发育所需因素的理解。

For membrane-bound intracellular parasites, the vacuole enclosing the pathogen is the portal of communication with the host cell. This membrane, therefore, functions in nutrient acquisition, protection against host defenses and in many cases must expand during infection to accommodate the developing parasite. We believe through the study of two Plasmodium proteins, UIS4 and the previously undescribed Lex3, which are present on the Plasmodium parasitophorous vacuole (PV) and its extended membrane network (TVN) in liver stage infections, we can better understand how this compartment carries out these functions. We choose these proteins because of their differential expression patterns: UIS4 is expressed early after infection and exclusively in liver cell infection, whereas Lex3 is expressed later in liver cell infection and also during blood infection. Therefore with these proteins we can compare membrane dynamics and the host cell influences of these dynamics at all mammalian infection stages. Intially we will precisely visualize and characterize the Lex3- and UIS4-positive structures in infected cells. Then, we will assess the contribution of host cytoskeletal elements and membrane transport pathways to the dynamics of the PV and TVN. Finally, we will search for host factors important for Plasmodium intracellular growth in part through identifying host protein interaction partners of UIS4 and Lex3. With these studies we will better characterize the Plasmodium-containing vacuole and improve our understanding of the factors necessary for Plasmodium intracellular development.