Wang Yifan, Fang Rui, Yuan Yuan, Pan Ming, Hu Min, Zhou Yanqin, Shen Bang, Zhao Junlong
State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, P. R. China.
The Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan, Hubei, P. R. China.
Parasitol Res. 2016 Jul;115(7):2825-35. doi: 10.1007/s00436-016-5033-2. Epub 2016 Apr 6.
As an obligate intracellular protozoan, Toxoplasma gondii is a successful pathogen infecting a variety of animals, including humans. As an adhesin involving in host invasion, the micronemal protein MIC3 plays important roles in host cell attachment, as well as modulation of host EGFR signaling cascade. However, the specific host proteins that interact with MIC3 are unknown and the identification of such proteins will increase our understanding of how MIC3 exerts its functions. This study was designed to identify host proteins interacting with MIC3 by yeast two-hybrid screens. Using MIC3 as bait, a library expressing mouse proteins was screened, uncovering eight mouse proteins that showed positive interactions with MIC3. Two of which, spermatogenesis-associated protein 3 (Spata3) and dickkopf-related protein 2 (Dkk2), were further confirmed to interact with MIC3 by additional protein-protein interaction tests. The results also revealed that the tandem repeat EGF domains of MIC3 were critical in mediating the interactions with the identified host proteins. This is the first study to show that MIC3 interacts with host proteins that are involved in reproduction, growth, and development. The results will provide a clearer understanding of the functions of adhesion-associated micronemal proteins in T. gondii.
作为一种专性细胞内原生动物，刚地弓形虫是一种成功的病原体，可感染包括人类在内的多种动物。作为一种参与宿主入侵的黏附素，微线体蛋白MIC3在宿主细胞黏附以及宿主表皮生长因子受体（EGFR）信号级联调节中发挥重要作用。然而，与MIC3相互作用的具体宿主蛋白尚不清楚，鉴定此类蛋白将增进我们对MIC3如何发挥其功能的理解。本研究旨在通过酵母双杂交筛选鉴定与MIC3相互作用的宿主蛋白。以MIC3为诱饵，筛选表达小鼠蛋白的文库，发现8种与MIC3呈阳性相互作用的小鼠蛋白。其中两种，精子发生相关蛋白3（Spata3）和 Dickkopf相关蛋白2（Dkk2），通过额外的蛋白质-蛋白质相互作用试验进一步证实与MIC3相互作用。结果还表明，MIC3的串联重复EGF结构域在介导与已鉴定的宿主蛋白的相互作用中起关键作用。这是第一项表明MIC3与参与生殖、生长和发育的宿主蛋白相互作用的研究。这些结果将使我们对刚地弓形虫中与黏附相关的微线体蛋白的功能有更清晰的了解。
