Binding of intimin from enteropathogenic Escherichia coli to Tir and to host cells
Binding of intimin from enteropathogenic Escherichia coli to Tir and to host cells
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DOI：
10.1046/j.1365-2958.1999.01338.x
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发表时间：
1999-04-01
影响因子：
3.6
通讯作者：
Frankel, G
中科院分区：
文献类型：
--
作者：
Hartland, EL;Batchelor, M;Frankel, G
肠致病性大肠杆菌（EPEC）可在上皮细胞上引起特征性的附着和消失（A/E）损伤。该事件部分地通过细菌外膜蛋白，内膜蛋白，与第二EPEC蛋白，Tir（易位的内膜蛋白受体）的结合介导，Tir由细菌输出并整合到宿主细胞质膜中。在这项研究中，我们已经定位的Tir的intimin结合域的中央107个氨基酸的区域，指定tir-M。我们提供的证据表明，氨基和羧基末端的TIR位于宿主细胞内。此外，使用免疫金标记电子显微镜，我们已经证实，即使在没有Tir的情况下，intimin也可以独立地与宿主细胞结合。这种Tir独立的相互作用和EPEC诱导A/E损伤的能力需要位于intimin多肽羧基末端的完整的凝集素样模块。使用酵母双杂交系统和凝胶覆盖，我们表明，即使在凝集素样结构域被破坏时，内膜可以结合Tir和Tir-M。这些数据提供了强有力的证据表明，不仅与Tir，但也在凝集素样的方式与宿主细胞内膜受体的相互作用。
Enteropathogenic Escherichia coli (EPEC) induce characteristic attaching and effacing (A/E) lesions on epithelial cells. This event is mediated, in part, by binding of the bacterial outer membrane protein, intimin, to a second EPEC protein, Tir (translocated intimin receptor), which is exported by the bacteria and integrated into the host cell plasma membrane. In this study, we have localized the intimin-binding domain of Tir to a central 107-amino-acid region, designated Tir-M. We provide evidence that both the amino- and carboxy-termini of Tir are located within the host cell. In addition, using immunogold labelling electron microscopy, we have confirmed that intimin can bind independently to host cells even in the absence of Tir, This Tir-independent interaction and the ability of EPEC to induce A/E lesions requires an intact lectinlike module residing at the carboxy-terminus of the intimin polypeptide. Using the yeast two-hybrid system and gel overlays, we show that intimin can bind both Tir and Tir-M even when the lectin-like domain is disrupted. These data provide strong evidence that intimin interacts not only with Tir but also in a lectinlike manner with a host cell intimin receptor.