Molecular dissection of Salmonella-induced membrane ruffling versus invasion
Molecular dissection of Salmonella-induced membrane ruffling versus invasion
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DOI：
10.1111/j.1462-5822.2009.01380.x
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发表时间：
2010-01-01
影响因子：
3.4
通讯作者：
Rottner, Klemens
中科院分区：
文献类型：
--
作者：
Haenisch, Jan;Ehinger, Julia;Rottner, Klemens
III型分泌系统介导的细菌蛋白混合物的注射驱动肌动蛋白重排，经常采用皱褶膜的突出突起的形状，并最终导致革兰氏阴性病原体如鼠伤寒沙门氏菌的宿主细胞入侵。不同的沙门氏菌效应子能够结合肌动蛋白并激活Rho家族GTP酶，其先前已经涉及通过与N-WASP或WAVE复合物相互作用介导肌动蛋白依赖性沙门氏菌进入，所述N-WASP或WAVE复合物是肌动蛋白成核机Arp 2/3复合物的公认激活剂。使用遗传缺失和RNA干扰的研究，我们在这里表明，无论是个人或集体去除这些Arp 2/3复合物激活剂影响宿主细胞的入侵有效Arp 2/3复合物敲低，虽然后者也不是必不可少的。然而，干扰WAVE复合物功能废除沙门氏菌诱导的膜皱褶，而不显着影响进入效率，肌动蛋白或Arp 2/3复合物的积累。此外，扫描电子显微镜图像捕获的进入事件中没有突出的膜皱褶。最后，定位和RNA干扰研究表明新型Arp 2/3复合物调节剂WASH在沙门氏菌进入中具有相关功能。这些数据首次建立了沙门氏菌入侵是从细菌诱导的膜皱褶分离，并揭示了一个额外的Arp 2/3复合物激活剂以及Arp 2/3复合物独立的肌动蛋白组装活性，有助于沙门氏菌入侵。
Type III secretion system-mediated injection of a cocktail of bacterial proteins drives actin rearrangements, frequently adopting the shape of prominent protuberances of ruffling membrane, and culminating in host cell invasion of Gram-negative pathogens like Salmonella typhimurium. Different Salmonella effectors are able to bind actin and activate Rho-family GTPases, which have previously been implicated in mediating actin-dependent Salmonella entry by interacting with N-WASP or WAVE-complex, well-established activators of the actin nucleation machine Arp2/3-complex. Using genetic deletion and RNA interference studies, we show here that neither individual nor collective removal of these Arp2/3-complex activators affected host cell invasion as efficiently as Arp2/3-complex knock-down, although the latter was also not essential. However, interference with WAVE-complex function abrogated Salmonella-induced membrane ruffling without significantly affecting entry efficiency, actin or Arp2/3-complex accumulation. In addition, scanning electron microscopy images captured entry events in the absence of prominent membrane ruffles. Finally, localization and RNA interference studies indicated a relevant function in Salmonella entry for the novel Arp2/3-complex regulator WASH. These data establish for the first time that Salmonella invasion is separable from bacteria-induced membrane ruffling, and uncover an additional Arp2/3-complex activator as well as an Arp2/3-complex-independent actin assembly activity that contribute to Salmonella invasion.