Rickettsial Actin‐Based Motility
Rickettsial Actin‐Based Motility
复制标题
基于立克次体肌动蛋白的运动
DOI：
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
R. Heinzen
中科院分区：
文献类型：
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作者：
R. Heinzen
摘要：基于肌动蛋白的运动（ABM）被斑点热族（SFG）立克次体（例如立克次体）利用来促进细胞间传播。延时视频显微镜显示，ABM 并不严格限于 SFG 立克次体，因为斑疹伤寒组伤寒立克次体的移动速度与立克次体大致相同（约 4 μm/min），但速度非常不稳定。在伤寒杆菌和立氏立克次体的 ABM 之间观察到许多共同的行为，例如进入质膜突起、仅在新形成的子细胞的旧表面上形成新的肌动蛋白尾部、以及在与阻碍向前运动的细胞结构接触时肌动蛋白尾部快速（在 15 秒内）重新组装到相反的极。最后的行为表明，ABM 所需的立克次体蛋白均匀地定位于细菌的两极，并且可能遍及整个立克次体表面。神经元 Wiskott-Aldrich 综合征蛋白 (N-WASP) 和肌动蛋白相关蛋白 (Arp)2/3 复合物（其他病原体 ABM 的关键调节因子）在立克次体 ABM 中的功能作用尚未确定。对 N-WASP 或 Arp2/3 复合体功能具有抑制作用的 N-WASP 结构域在感染立克次体的 HeLa 细胞中表达。使用福氏志贺氏菌感染的细胞作为对照。当异位表达时，N-WASP (VCA) 的 VCA 结构域对于 Arp2/3 复合体功能起显性/负向作用，而缺失 VCA 的 N-WASP (ΔVCA) 则作为 N-WASP 的显性/负向形式。 VCA或ΔVCA的表达严重抑制弗氏沙门氏菌ABM（在大多数表达细胞中未观察到志贺氏菌运动性），而仅中度抑制立克次氏立克氏菌的ABM（ABM率降低约35%）。此外，异位表达的全长 GFP-N-WASP 被福氏沙门氏菌募集，但立氏立克次体不被募集，并且通过间接免疫荧光在福氏沙门氏菌肌动蛋白尾部检测到 Arp3，但在立克次氏立克次体肌动蛋白尾部中未检测到 Arp3。总的来说，这些数据表明立克次体 ABM 独立于 N-WASP 和 Arp2/3 复合体功能。
Abstract: Actin‐based motility (ABM) is employed by spotted fever group (SFG) rickettsiae, such as Rickettsia rickettsii, to promote cell‐to‐cell spread. Time‐lapse video microscopy revealed that ABM is not strictly confined to SFG rickettsiae as typhus group R. typhi moved at approximately the same rate as R. rickettsii (approximately 4 μm/min), but in a highly erratic fashion. A number of common behaviors were observed between ABM of R. typhi and R. rickettsii, such as entrance into plasma membrane protrusions, formation of new actin tails only on the old surface of newly formed daughter cells, and quick (within 15 sec) reassembly of the actin tail to the opposite pole upon contact with cellular structures that impede forward movement. This last behavior suggests that the rickettsial protein(s) required for ABM is uniformly localized to both poles of the bacterium and possibly throughout the rickettsial surface. Functional roles in rickettsial ABM for neuronal Wiskott‐Aldrich syndrome protein (N‐WASP) and the actin‐related protein (Arp)2/3 complex, critical regulators of ABM of other pathogens, have not been established. Domains of N‐WASP that have characterized inhibitory effects on N‐WASP or Arp2/3 complex function were expressed in HeLa cells infected with R. rickettsii. Shigella flexneri‐infected cells were used as a control. When ectopically expressed, the VCA domain of N‐WASP (VCA) acts as a dominant/negative with respect to Arp2/3 complex function and N‐WASP missing VCA (ΔVCA) acts as a dominant/negative form of N‐WASP. Expression of VCA or ΔVCA severely inhibited S. flexneri ABM (no Shigella motility observed in the majority of expressing cells) while only moderately inhibiting ABM of R. rickettsii (approximately 35% decrease in the rate of ABM). In addition, ectopically expressed full‐length GFP‐N‐WASP was recruited by S. flexneri but not R. rickettsii, and Arp3 was detected by indirect immunofluorescence in S. flexneri actin tails but not within R. rickettsii actin tails. Collectively, these data suggest that rickettsial ABM is independent of N‐WASP and Arp2/3 complex function.
影响因子：
56.9
作者：
Welch, MD;Rosenblatt, J;Mitchison, TJ
通讯作者：
Mitchison, TJ
DOI：
10.1073/pnas.96.7.3739
发表时间：
1999-03-30
影响因子：
11.1
作者：
Machesky, LM;Mullins, RD;Pollard, TD
通讯作者：
Pollard, TD
DOI：
10.1073/pnas.96.9.4908
发表时间：
1999-04-27
影响因子：
11.1
作者：
Cameron, LA;Footer, MJ;Theriot, JA
通讯作者：
Theriot, JA