四型分泌系统在促进布鲁氏菌免疫逃避、胞内生存、形成慢性感染过程中发挥重要作用，目前发现该系统分泌15个效应蛋白，但是大多数的功能和作用机制尚未阐明。我们的前期研究发现，效应蛋白BPE005为布鲁氏菌胞内生存所必须，且与宿主蛋白WASH存在相互作用。因此，本项目拟在分析BPE005突变株体内、体外表型的基础上，重点研究BPE005对细胞功能的影响；基于蛋白相互作用分析BPE005作用于WASH的生化基础及对下游分子事件的影响；采用细胞生物学技术分析WASH如何介导BCV（含布鲁氏菌囊泡）的胞内转运过程，包括逃避溶酶体杀伤、定位至内质网、逃避自噬降解。总之，本项目通过阐明BPE005在布鲁氏菌寄生过程中的功能和作用机制，有助于深入理解布鲁氏菌慢性感染的分子机制，为开发新的疫苗和治疗药物提供理论基础。

Type 4 Secretion System(T4SS) play vital roles in helping Brucella evading host killing mechanisms and promoting intracellular survival. Recently, 15 effector proteins secreted through T4SS were identified, but functions of most of them remain unclear. In previous work, we found that the effector protein could bind to the host protein WASH, and their functions were tightly associated. Therefore, we will analyze how BPE005 promote intracellular survival of Brucella through manipulating WASH during infection. Based on in vitro and in vivo phenotype of BPE005 mutant, functions of BPE005 in transfected cells are analyzed; how BPE005 binds to WASH and effects of interaction between them are then be assayed; the con-focal microscopy are used to detect how WASH mediates BCV localization and evasion of intracellular anti-bacterial activities. In conclusion, this project aims to clarify key roles and molecular mechanisms of BPE005 during promoting intracellular survival of Brucella, which may be helpful for further understanding Brucella pathogenesis and useful for developing new drug targets and vaccines.