IpgD, a protein secreted by the type III secretion machinery of Shigella flexneri, is chaperoned by IpgE and implicated in entry focus formation
IpgD, a protein secreted by the type III secretion machinery of Shigella flexneri, is chaperoned by IpgE and implicated in entry focus formation
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IpgD 是福氏志贺氏菌 III 型分泌机制分泌的一种蛋白质，由 IpgE 陪伴并参与进入病灶的形成
作者：
K. Niebuhr;Noureddine Jouihri;A. Allaoui;P. Gounon;P. Sansonetti;C. Parsot
福氏志贺菌对上皮细胞的侵袭包括侵入和细胞间播散。细菌进入非吞噬细胞需要Mxi-Spa III型分泌机制分泌的IpaA-D蛋白。III型分泌系统存在于几种革兰氏阴性病原体中，用于将细菌效应蛋白直接注入宿主细胞的细胞质中。在本研究中，我们分析了S.该基因位于毒力质粒的5′端，位于MXI-SPA基因座的5′端。我们已经表明，IpgD（i）与特异性伴侣IpgE一起储存在细菌细胞质中;（ii）由Mxi-Spa III型分泌系统以与IpaA-D蛋白相似的量分泌;（iii）与细胞外介质中的IpaA相关;以及（iv）在细菌与上皮细胞接触后参与宿主细胞应答的调节。这表明IpgD是一种效应物，可能被注射到宿主细胞中以在感染期间操纵细胞过程。
Invasion of epithelial cells by Shigella flexneri involves entry and intercellular dissemination. Entry of bacteria into non‐phagocytic cells requires the IpaA–D proteins that are secreted by the Mxi–Spa type III secretion machinery. Type III secretion systems are found in several Gram‐negative pathogens and serve to inject bacterial effector proteins directly into the cytoplasm of host cells. In this study, we have analysed the IpgD protein of S. flexneri, the gene of which is located on the virulence plasmid at the 5′ end of the mxi–spa locus. We have shown that IpgD (i) is stored in the bacterial cytoplasm in association with a specific chaperone, IpgE; (ii) is secreted by the Mxi–Spa type III secretion system in amounts similar to those of the IpaA–D proteins; (iii) is associated with IpaA in the extracellular medium; and (iv) is involved in the modulation of the host cell response after contact of the bacterium with epithelial cells. This suggests that IpgD is an effector that might be injected into host cells to manipulate cellular processes during infection.