Spatial separation of FtsZ and FtsN during cell division
Spatial separation of FtsZ and FtsN during cell division
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DOI：
10.1111/mmi.13888
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发表时间：
2018-02-01
影响因子：
3.6
通讯作者：
Daley, Daniel O.
中科院分区：
文献类型：
--
作者：
Soderstrom, Bill;Chan, Helena;Daley, Daniel O.
大肠杆菌的分裂是由大约34种不同的蛋白质组成的集合所介导的，这些蛋白质被招募到分裂隔膜，并被认为组装成一个被称为分裂体的大分子复合体。在这里，我们试图通过成像其两个核心成分FtsZ和FtsN来更好地了解分裂体的结构。超分辨显微镜(SIM和gSTED)表明，这两种蛋白质都定位在大的集合体中，分布在分裂隔膜周围(即形成一个不连续的环)。虽然环在收缩之前具有相似的半径，但个体密度在圆周上往往是空间上分离的。随着细胞被膜的收缩，FtsZ形成的不连续环向FtsN形成的不连续环内部移动。在我们的图像中观察到的径向和周向分离表明，大多数FtsZ和FtsN分子是在不同的大分子组装中组织的，而不是在一个大的超复合体中。这一结论得到了光漂白后的荧光恢复的支持，这表明这两个大分子组装的动力学行为也是完全不同的。综上所述，这些数据表明，细胞包膜的收缩是由(至少)两个空间上分离的复合体引起的。
The division of Escherichia coli is mediated by a collection of some 34 different proteins that are recruited to the division septum and are thought to assemble into a macromolecular complex known as the divisome'. Herein, we have endeavored to better understand the structure of the divisome by imaging two of its core components; FtsZ and FtsN. Super resolution microscopy (SIM and gSTED) indicated that both proteins are localized in large assemblies, which are distributed around the division septum (i.e., forming a discontinuous ring). Although the rings had similar radii prior to constriction, the individual densities were often spatially separated circumferentially. As the cell envelope constricted, the discontinuous ring formed by FtsZ moved inside the discontinuous ring formed by FtsN. The radial and circumferential separation observed in our images indicates that the majority of FtsZ and FtsN molecules are organized in different macromolecular assemblies, rather than in a large super-complex. This conclusion was supported by fluorescence recovery after photobleaching measurements, which indicated that the dynamic behavior of the two macromolecular assemblies was also fundamentally different. Taken together, the data indicates that constriction of the cell envelope is brought about by (at least) two spatially separated complexes.