弓形虫是广泛分布的细胞内寄生原虫，在免疫抑制病人及胎儿感染中引起严重疾病甚至死亡。弓形虫感染宿主并产生病理损伤，依赖于寄生虫分子与宿主细胞蛋白的互作。目前对弓形虫毒力调节因子的发现及鉴定是弓形虫毒力机制研究的热点，却少有研究深入到毒力调节因子对宿主细胞的调控等方面。ROP18是弓形虫重要的毒力调节因子，与虫株毒力密切相关，在不同毒株中具有多态性。本项目拟应用基于双分子荧光互补技术(BiFC)的平台从人蛋白库中高通量地筛选弓形虫不同毒株ROP18的互作蛋白，并用CO-IP及FRET验证其互作；比较不同毒株ROP18互作蛋白谱的差异并绘制其互作网络图；敲除细胞ROP18互作蛋白基因测试其对弓形虫毒力效率的影响；观察互作蛋白对在细胞内的共定位及对宿主细胞信号通路活化的作用。从而阐明宿主细胞互作蛋白介导的弓形虫ROP18毒力的机制，对理解弓形虫的致病机制及寻找有效的药物靶点具有重大的意义。

Toxoplasma gondii is a widely distributed intracellular parasitic protozoa, and may cause severe illness and even death in immunosuppressive patients and fetal infection. The processes of Toxoplasma gondii invading host cells and causing pathological injury, depend on the interaction of the parasite molecules with the host cell proteins. The current researches on Toxoplasma virulence mechanism are focused on the discovery and identification of virulence mediating factors , only few of them are involved deeply into the host cell regulation etc. ROP18 is an important virulence mediating factor of Toxoplasma gondii, which is closely related to the strain virulence, and exhibits polymorphism in different strains. This project aims to screen the human proteins interacting with the ROP18s from different strains of Toxoplasma gondii from the human protein library in high-throughput, with the interaction protein screening platform based on the technology of Biomolecular Fluorescence Complementation Assay (BiFC). CO-IP and FRET will be used to identify its interaction; the profiles of the host proteins interacting with the ROP18s from different strains will be compared and the interaction network diagram will be drawn. ROP18 interaction protein genes will be knocked out from the host cell to detect the virulence efficiency of Toxoplasma gondii in infection. Co-localization of ROP18 with its interaction host proteins and the effects on the host cell signaling will be observed. From above researches, the mechanism of ROP18 virulence medicated by the host interaction proteins will be more clear, and it is important for understanding of Toxoplasma gondii pathogenesis mechanism, and finding of the effective drug targets.