Release of outer membrane vesicles by Gram-negative bacteria is a novel envelope stress response.
Release of outer membrane vesicles by Gram-negative bacteria is a novel envelope stress response.
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DOI：
10.1111/j.1365-2958.2006.05522.x
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发表时间：
2007-01
影响因子：
3.6
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中科院分区：
文献类型：
--
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破坏革兰氏阴性细菌包膜中蛋白质折叠的条件会引起应激。应力在这个隔室中的不稳定效应被许多信号转导机制所识别和抵消。这里提供的数据揭示了复杂细菌应激反应的另一个方面，即外膜囊泡的释放。天然囊泡由外膜和质周物质组成，它们从细菌表面释放而不损失膜的完整性。在这里，我们证明囊泡释放的数量与细胞包膜中蛋白质积累的水平直接相关。物质的积累发生在压力下，并在细胞的正常内护和应激反应机制受损时加剧。引起囊泡增加的突变可以提高细菌在应激剂或有毒错误折叠蛋白质积累的挑战下的存活率。将错误折叠的蛋白质模拟物优先包装到囊泡中以进行去除，表明囊泡过程可以选择性地消除不需要的物质。我们的研究结果表明，细菌外膜囊泡的产生是一种完全独立的、一般的包膜应激反应。除了确定一种缓解应激的新机制外，这项工作还提供了囊泡产生作为一种保护机制的生理学相关性。
Conditions that impair protein folding in the Gram-negative bacterial envelope cause stress. The destabilizing effects of stress in this compartment are recognized and countered by a number of signal transduction mechanisms. Data presented here reveal another facet of the complex bacterial stress response, release of outer membrane vesicles. Native vesicles are composed of outer membrane and periplasmic material, and they are released from the bacterial surface without loss of membrane integrity. Here we demonstrate that the quantity of vesicle release correlates directly with the level of protein accumulation in the cell envelope. Accumulation of material occurs under stress, and is exacerbated upon impairment of the normal housekeeping and stress-responsive mechanisms of the cell. Mutations that cause increased vesiculation enhance bacterial survival upon challenge with stressing agents or accumulation of toxic misfolded proteins. Preferential packaging of a misfolded protein mimic into vesicles for removal indicates that the vesiculation process can act to selectively eliminate unwanted material. Our results demonstrate that production of bacterial outer membrane vesicles is a fully independent, general envelope stress response. In addition to identifying a novel mechanism for alleviating stress, this work provides physiological relevance for vesicle production as a protective mechanism.