Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA.
Physiology Course, Marine Biological Laboratory, Woods Hole, MA, USA.
Nat Microbiol. 2021 May;6(5):553-562. doi: 10.1038/s41564-021-00878-z. Epub 2021 Mar 18.
Although many components of the cell division machinery in bacteria have been identified, the mechanisms by which they work together to divide the cell remain poorly understood. Key among these components is the tubulin FtsZ, which forms a Z ring at the midcell. FtsZ recruits the other cell division proteins, collectively called the divisome, and the Z ring constricts as the cell divides. We applied live-cell single-molecule imaging to describe the dynamics of the divisome in detail, and to evaluate the individual roles of FtsZ-binding proteins (ZBPs), specifically FtsA and the ZBPs EzrA, SepF and ZapA, in cytokinesis. We show that the divisome comprises two subcomplexes that move differently: stationary ZBPs that transiently bind to treadmilling FtsZ filaments, and a moving complex that includes cell wall synthases. Our imaging analyses reveal that ZBPs bundle FtsZ filaments together and condense them into Z rings, and that this condensation is necessary for cytokinesis.
尽管已经鉴定出细菌细胞分裂机制的许多组成部分，但它们协同作用将细胞分裂的机制仍知之甚少。这些成分中最重要的是微管蛋白 FtsZ，它在细胞中部形成 Z 环。FtsZ 招募其他细胞分裂蛋白，统称为分裂体，随着细胞分裂，Z 环收缩。我们应用活细胞单分子成像技术详细描述了分裂体的动力学，并评估了 FtsZ 结合蛋白（ZBPs），特别是 FtsA 和 ZBPs EzrA、SepF 和 ZapA，在细胞分裂中的作用。我们表明，分裂体由两个移动方式不同的亚复合物组成：瞬时结合在踏车式 FtsZ 丝上的静止 ZBPs，以及包含细胞壁合成酶的移动复合物。我们的成像分析表明，ZBPs 将 FtsZ 丝束在一起并将其浓缩成 Z 环，这种浓缩对于细胞分裂是必要的。
