Nature：发现大肠杆菌粘附肠壁新机制

大肠杆菌利用鞭毛附着在肠壁上

肠毒性大肠杆菌是发展中国家最常见的腹泻原因，也是旅行者腹泻的主要原因。粘附到宿主细胞上是这种及很多其他种细菌病原体致病所必需的。
现在，研究人员发现了大肠杆菌的一个新的粘附机制，该机制依赖于体内分泌的蛋白EtpA。该蛋白与细菌鞭毛顶端的鞭毛蛋白分子的保留区域发生相互作用，在那里它形成细菌与宿主细胞之间的一个粘附分子桥。这一发现是证明EtpA（以及保留下来的鞭毛蛋白配体）有可能是针对大肠杆菌及其他运动病原体（motile pathogen）的疫苗的有效抗原目标的又一个证据。（生物谷Bioon.com）
Bioon推荐原始出处：
Nature 457, 594-598 (29 January 2009) doi:10.1038/nature07568
Enterotoxigenic Escherichia coli EtpA mediates adhesion between flagella and host cells
Koushik Roy1, George M. Hilliard2, David J. Hamilton3, Jiwen Luo1, Marguerite M. Ostmann4 & James M. Fleckenstein1,2,5
1 Department of Medicine,2 Department of Molecular Sciences,3 Department of Comparative Medicine, University of Tennessee Health Science Center, 956 Court Avenue, Memphis, Tennessee 38163, Tennessee, USA
Adhesion to epithelial cells1 and flagella-mediated motility are critical virulence traits for many Gram-negative pathogens, including enterotoxigenic Escherichia coli (ETEC)2, a major cause of diarrhoea in travellers and children in developing countries3, 4. Many flagellated pathogens export putative adhesins belonging to the two-partner secretion (TPS) family5. However, the actual function of these adhesins remains largely undefined. Here we demonstrate that EtpA, a TPS exoprotein adhesin of enterotoxigenic E. coli 6, mimics and interacts with highly conserved regions of flagellin, the major subunit of flagella, and that these interactions are critical for adherence and intestinal colonization. Although conserved regions of flagellin are mostly buried in the flagellar shaft7, our results suggest that they are at least transiently exposed at the tips of flagella where they capture EtpA adhesin molecules for presentation to eukaryotic receptors. Similarity of EtpA to molecules encoded by other motile pathogens suggests a potential common pattern for bacterial adhesion, whereas participation of conserved regions of flagellin in adherence has implications for development of vaccines for Gram-negative pathogens.