A Fluorescent Reporter Reveals On/Off Regulation of the Shigella Type III Secretion Apparatus during Entry and Cell-to-Cell Spread
A Fluorescent Reporter Reveals On/Off Regulation of the Shigella Type III Secretion Apparatus during Entry and Cell-to-Cell Spread
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DOI：
10.1016/j.chom.2014.01.005
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发表时间：
2014-02-12
影响因子：
30.3
通讯作者：
Parsot, Claude
中科院分区：
文献类型：
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作者：
Campbell-Valois, Francois-Xavier;Schnupf, Pamela;Parsot, Claude
许多致病的革兰氏阴性菌使用三型分泌器(T3SA)将效应蛋白转运到宿主细胞中。在完整的宿主细胞内检测和监测细胞内细菌的T3SA一直是具有挑战性的。利用福氏志贺氏菌T3S效应基因转录和T3SA活性之间的紧密耦合，以及快速成熟的绿色荧光蛋白，我们开发了实时监测T3SA活性的报告。这些记者揭示了T3SA在感染过程中的动态时间规律。T3SA最初在细菌进入时被激活，随后当细菌进入宿主细胞细胞质时下调，从而允许补充入侵邻近细胞所需的T3S底物的细菌存储。T3SA的重新激活严格依赖于细胞间扩散过程中基于肌动蛋白的运动性和质膜突起的形成。因此，T3SA在细菌细胞内的生态位内受到严格的开关调节。
Numerous pathogenic Gram-negative bacteria use a type three secretion apparatus (T3SA) to translocate effector proteins into host cells. Detecting and monitoring the T3SA of intracellular bacteria within intact host cells has been challenging. Taking advantage of the tight coupling between T3S effector-gene transcription and T3SA activity in Shigella flexneri, together with a fast-maturing green fluorescent protein, we developed reporters to monitor T3SA activity in real time. These reporters reveal a dynamic temporal regulation of the T3SA during the course of infection. T3SA is activated initially during bacterial entry and downregulated subsequently when bacteria gain access to the host cell cytoplasm, allowing replenishment of the bacterial stores of T3S substrates necessary for invading neighboring cells. Reactivation of the T3SA was strictly dependent on actin-based motility and formation of plasma membrane protrusions during cell-to-cell spread. Thus, the T3SA is subject to a tight on/off regulation within the bacterial intracellular niche.