Centre for Molecular Microbiology and Infection, Imperial College, London SW7 2AZ, UK.
Cell Microbiol. 2011 Sep;13(9):1429-39. doi: 10.1111/j.1462-5822.2011.01631.x. Epub 2011 Jul 11.
The enteric pathogens enteropathogenic Escherichia coli (EPEC), enterohaemorrhagic E. coli (EHEC) and Shigella flexneri all translocate at least one effector protein of the EspG protein family into host cells via a type III secretion system (T3SS). The EspG family comprises EspG, EspG2 and VirA. From a Y2H screen, we identified the Golgi matrix protein GM130 as a potential binding partner of EspG. We confirmed EspG:GM130 protein interaction by affinity co-purification. In co-immunoprecipitation experiments EspG was co-precipitated with GM130 while both GM130 and tubulins were co-precipitated with EspG. When expressed ectopically in HeLa cells, the EspG protein family all localized to the Golgi and induced fragmentation of the Golgi apparatus. All EspG family proteins were also able to disrupt protein secretion to a greater extent than the T3SS effector NleA/EspI, which has previously been shown to localize to the Golgi and interact with SEC24 to disrupt COPII vesicle formation. We hypothesize that EspG:GM130 interaction disrupts protein secretion either through direct disruption of GM130 function or through recruitment of other EspG interacting proteins to the Golgi.
肠致病性大肠杆菌（EPEC）、肠出血性大肠杆菌（EHEC）和志贺氏菌均通过 III 型分泌系统（T3SS）将至少一种 EspG 蛋白家族的效应蛋白转运至宿主细胞。EspG 家族包括 EspG、EspG2 和 VirA。通过 Y2H 筛选，我们鉴定出高尔基基质蛋白 GM130 是 EspG 的潜在结合伴侣。我们通过亲和共纯化证实了 EspG:GM130 蛋白相互作用。在共免疫沉淀实验中，EspG 与 GM130 共沉淀，而 GM130 和微管蛋白均与 EspG 共沉淀。当在 HeLa 细胞中异位表达时，EspG 蛋白家族均定位于高尔基体并诱导高尔基体的碎片化。所有 EspG 家族蛋白都能比 T3SS 效应蛋白 NleA/EspI 更显著地破坏蛋白质分泌，后者先前已被证明定位于高尔基体并与 SEC24 相互作用以破坏 COPII 囊泡形成。我们假设 EspG:GM130 相互作用通过直接破坏 GM130 功能或通过招募其他 EspG 相互作用蛋白到高尔基体来破坏蛋白质分泌。
