Zhang Xiaoyan, Zeng Bangwei, Wen Chunyan, Zheng Shurong, Chen Hao, She Feifei
Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Fujian Medical University, 1 Xuefu North Road, University Town, Fuzhou, Fujian Province 350122, PR China.
Fujian Key Laboratory of Tumor Microbiology, School of Basic Medical Sciences, Fujian Medical University, 1 Xuefu North Road, University Town, Fuzhou, Fujian Province 350122, PR China.
FEMS Microbiol Lett. 2018 Feb 1;365(2). doi: 10.1093/femsle/fnx231.
CagA, an important virulence factor of Helicobacter pylori, targets and interacts with a series of host proteins to activate signaling factors involved in many functions, such as development, cytoskeleton rearrangement and inflammatory molecule release. Despite extensive efforts, the relationship between CagA and gastric cancer is far from completely understood. Here, the GAL4 yeast two-hybrid system was used to screen cellular proteins for binding to CagA, and five cellular proteins, including tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, epsilon (YWHAE), were identified. The CagA-YWHAE interaction was further verified not only in vitro by a glutathione S-transferase pull-down assay, but also in vivo by immunolocalization and co-immunoprecipitation assays. In SGC7901 and AGS cells, overexpression of the YWHAE protein promoted the activation of NF-κB by CagA; conversely, knockdown of the YWHAE protein inhibited the activation of NF-κB by CagA. These results indicate that CagA enhances the YWHAE-mediated transactivation of NF-κB, providing a new clue to the molecular mechanisms of H. pylori-associated tumorigenesis mediated by CagA.
细胞毒素相关基因A（CagA）是幽门螺杆菌的一种重要毒力因子，它作用于一系列宿主蛋白并与之相互作用，从而激活参与多种功能的信号因子，如发育、细胞骨架重排和炎症分子释放。尽管人们付出了巨大努力，但CagA与胃癌之间的关系仍远未完全明确。在此，利用GAL4酵母双杂交系统筛选与CagA结合的细胞蛋白，鉴定出了5种细胞蛋白，包括酪氨酸3-单加氧酶/色氨酸5-单加氧酶激活蛋白ε（YWHAE）。不仅通过谷胱甘肽S-转移酶下拉实验在体外进一步验证了CagA与YWHAE的相互作用，还通过免疫定位和免疫共沉淀实验在体内进行了验证。在SGC7901和AGS细胞中，YWHAE蛋白的过表达促进了CagA对核因子κB（NF-κB）的激活；相反，YWHAE蛋白的敲低则抑制了CagA对NF-κB的激活。这些结果表明，CagA增强了YWHAE介导的NF-κB反式激活，为CagA介导的幽门螺杆菌相关肿瘤发生的分子机制提供了新线索。
