疟原虫RON2-AMA1蛋白嵌合结构在入侵宿主细胞过程中功能研究

Malaria is a major human parasitic disease. Understanding the process of Plasmodium parasites invasion of host cells is crucial for vaccine design and new drug development. Our previous study characterized Plasmodium falciparum RON2 for its protein structure, transcription profiles, intracellular location, and complex formation with PfAMA1. Recent studies demonstrated that RON2 bind with AMA1 with disulfide bond, and presumed that which may directly involved in the formation of moving junction during invasion. While based on related studies, we hypothesis that RON2-AMA1 complex may not from the moving junction directly, but may be important for AMA1 to be clipped form the parasite surface, which is performed by an enzyme called PfSUB2, and the binding by RON2 may initial this step. The project is to confirm the function of RON2 disulfide bond in RON2-AMA1 complex, to analysis the function of RON2-AMA1 co-structure in Plasmodium for host erythrocyte and hepatocyte invasion, and to characterization how RON2-AMA1 binding structure effect the AMA1 cleavage, which will provide the invaluable information on the molecular mechanism of apicomplexa host cell invasion.

疟疾是严重危害人类健康的寄生虫病，疟原虫入侵宿主细胞机制的研究有助于疟疾疫苗和药物的研发。本实验室率先在疟原虫体内鉴定发现RON2蛋白的存在，并观察到它和AMA1蛋白形成复合体。其他科研工作者随后发现RON2通过二硫键构成的环状结构与AMA1蛋白的疏水凹槽嵌合，并推测该结构可能直接参与入侵过程中移动联接的构成。本项目根据相关研究结果对这一推论提出质疑，并形成"RON2-AMA1蛋白嵌合结构并不直接参与移动联接的构成，而可能参与疟原虫结束入侵前AMA1蛋白被SUB2水解酶切的调节作用"的假说。拟对疟原虫RON2二硫键结构在RON2-AMA1复合体形成中作用进行确认；并对RON2-AMA1嵌合结构在疟原虫入侵红细胞和肝细胞过程中的作用进行分析；还就RON2与AMA1蛋白的结合对AMA1蛋白水解过程的调控作用进行探讨，从而验证所提出的假说，为顶复门生物入侵宿主细胞分子机制的认识提供新的线索。

疟疾是严重危害人类健康的寄生虫病，以阻断疟原虫子孢子入侵肝细胞及其进一步发育为目标的红前期抗感染疟疾疫苗是目前较为有希望途径。本项目根据研究计划，对疟原虫棒状体蛋白 RON2 在疟原虫入侵肝细胞过程中的功能的进行了鉴定，对RON2与AMA1蛋白复合体在疟原虫入侵红细胞和肝细胞过程中的作用进行了分析，从而评估了该蛋白作为疟疾疫苗候选分子的潜在价值。此外，在本项目支持下，课题组还对重症恶性疟致病机理和疟原虫对抗疟药的抗性开展了研究。