Kenny B, Finlay B B
Biotechnology Laboratory, University of British Columbia, Vancouver, Canada.
Proc Natl Acad Sci U S A. 1995 Aug 15;92(17):7991-5. doi: 10.1073/pnas.92.17.7991.
Enteropathogenic Escherichia coli (EPEC), a major cause of pediatric diarrhea, adheres to epithelial cells and activates host cell signal transduction pathways. We have identified five proteins that are secreted by EPEC and show that this secretion process is critical for triggering signal transduction events in epithelial cells. Protein secretion occurs via two pathways: one secretes a 110-kDa protein and the other mediates export of the four remaining proteins. Secretion of all five proteins was regulated by temperature and the perA locus, two factors which regulate expression of other known EPEC virulence factors. Amino-terminal sequence analysis of the secreted polypeptides identified one protein (37 kDa) as the product of the eaeB gene, a genetic locus previously shown to be necessary for signal transduction. A second protein (39 kDa) showed significant homology with glyceraldehyde-3-phosphate dehydrogenase, while the other three proteins (110, 40, and 25 kDa) were unique. The secreted proteins associated with epithelial cells, and EaeB became resistant to protease digestion upon association, suggesting that intimate interactions are required for transducing signals.
肠致病性大肠杆菌（EPEC）是小儿腹泻的主要病因，它粘附于上皮细胞并激活宿主细胞信号转导通路。我们已鉴定出EPEC分泌的五种蛋白质，并表明这种分泌过程对于触发上皮细胞中的信号转导事件至关重要。蛋白质分泌通过两条途径进行：一条途径分泌一种110 kDa的蛋白质，另一条途径介导其余四种蛋白质的输出。所有五种蛋白质的分泌均受温度和perA位点调控，这两个因素也调控其他已知EPEC毒力因子的表达。对分泌多肽进行的氨基末端序列分析确定一种蛋白质（37 kDa）是eaeB基因的产物，该基因位点先前已证明对信号转导是必需的。第二种蛋白质（39 kDa）与甘油醛-3-磷酸脱氢酶具有显著同源性，而其他三种蛋白质（110、40和25 kDa）则是独特的。分泌的蛋白质与上皮细胞相关联，并且EaeB在关联后对蛋白酶消化产生抗性，这表明转导信号需要紧密相互作用。
