Phillips A D
University Department of Paediatric Gastroenterology, Royal Free Hospital, Pond Street, London NW3 2QG, UK.
Gut. 1998 Oct;43(4):456-7. doi: 10.1136/gut.43.4.456.
Enteropathogenic Escherichia coli (EPEC), like many bacterial pathogens, employ a type III secretion system to deliver effector proteins across the bacterial cell. In EPEC, four proteins are known to be exported by a type III secretion system--EspA, EspB and EspD required for subversion of host cell signal transduction pathways and a translocated intimin receptor (Tir) protein (formerly Hp90) which is tyrosine-phosphorylated following transfer to the host cell to become a receptor for intimin-mediated intimate attachment and "attaching and effacing" (A/E) lesion formation. The structural basis for protein translocation has yet to be fully elucidated for any type III secretion system. Here, we describe a novel EspA-containing filamentous organelle that is present on the bacterial surface during the early stage of A/E lesion formation, forms a physical bridge between the bacterium and the infected eukaryotic cell surface and is required for the translocation of EspB into infected epithelial cells.
肠致病性大肠杆菌（EPEC）与许多细菌病原体一样，利用III型分泌系统将效应蛋白转运穿过细菌细胞。在EPEC中，已知有四种蛋白质通过III型分泌系统输出——EspA、EspB和EspD是颠覆宿主细胞信号转导途径所必需的，还有一种转位紧密黏附素受体（Tir）蛋白（以前称为Hp90），它在转移到宿主细胞后会发生酪氨酸磷酸化，成为紧密黏附素介导的紧密附着和“黏附并抹除”（A/E）损伤形成的受体。对于任何III型分泌系统，蛋白质转运的结构基础尚未完全阐明。在这里，我们描述了一种新型的含EspA的丝状细胞器，它在A/E损伤形成的早期阶段存在于细菌表面，在细菌与受感染的真核细胞表面之间形成物理桥梁，并且是EspB转运到受感染上皮细胞所必需的。
