MinC, MinD, and MinE drive counter-oscillation of early-cell-division proteins prior to Escherichia coli septum formation.
MinC, MinD, and MinE drive counter-oscillation of early-cell-division proteins prior to Escherichia coli septum formation.
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DOI：
10.1128/mbio.00856-13
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发表时间：
2013-12-10
期刊：
影响因子：
6.4
通讯作者：
Sherratt D
中科院分区：
文献类型：
--
作者：
Bisicchia P;Arumugam S;Schwille P;Sherratt D
细菌细胞分裂起始于在细胞中心形成由微管蛋白同源物FtsZ（Z环）组成的环状结构，其充当细胞分裂复合物（分裂体）组装的支架。以前的研究表明，分裂体最初由膜锚FtsA和ZipA稳定的FtsZ聚合物组成，然后招募剩余的分裂蛋白。MinCDE蛋白通过在两极之间振荡来防止Z环在两极形成，从而确保Z环抑制剂MinC的浓度在细胞中心最低。我们发现，在隔膜形成之前，早期分裂蛋白ZipA，ZapA和ZapB，沿着FtsZ，组装成复合物，相对于MinC反向振荡，并具有相同的周期。我们提出，FtsZ分子远离高浓度的MinC形成相对缓慢扩散的细丝，这些细丝被ZapAB结合，并通过ZipA或FtsA靶向内膜。这些复合物可以促进分裂体组装在中细胞的早期阶段。由于MinC向这些复合物振荡，FtsZ寡聚化和成束被抑制，导致较短或单体的FtsZ复合物，由于其快速扩散，其通过落射荧光显微镜变得不太可见。重建的FtsZ-最小波脂质双层显示，FtsZ束分区远离高浓度的MinC和ZapA似乎保护FtsZ从MinC通过抑制FtsZ营业额。在过去的100年里，生物学的一个大问题是细胞如何找到它的中间。在大肠杆菌中，超过20种蛋白质在分裂时在细胞中心组装。我们表明，MinCDE蛋白，防止隔膜的形成在细胞极抑制FtsZ，驱动反振荡的早期细胞分裂蛋白ZapA，ZapB和ZipA，沿着与FtsZ。我们建议，FtsZ在极的MinC浓度最低的地方形成细丝，并作为ZapA，ZapB和ZipA的结合的支架：这种复合物被分解的MinC和改革内的MinC振荡周期，然后在分裂时积累在细胞中心。FtsZ以与ZipA和ZapAB结合的寡聚体形式靶向细胞中心的能力可能促进分裂体组装的早期阶段。
Bacterial cell division initiates with the formation of a ring-like structure at the cell center composed of the tubulin homolog FtsZ (the Z-ring), which acts as a scaffold for the assembly of the cell division complex, the divisome. Previous studies have suggested that the divisome is initially composed of FtsZ polymers stabilized by membrane anchors FtsA and ZipA, which then recruit the remaining division proteins. The MinCDE proteins prevent the formation of the Z-ring at poles by oscillating from pole to pole, thereby ensuring that the concentration of the Z-ring inhibitor, MinC, is lowest at the cell center. We show that prior to septum formation, the early-division proteins ZipA, ZapA, and ZapB, along with FtsZ, assemble into complexes that counter-oscillate with respect to MinC, and with the same period. We propose that FtsZ molecules distal from high concentrations of MinC form relatively slowly diffusing filaments that are bound by ZapAB and targeted to the inner membrane by ZipA or FtsA. These complexes may facilitate the early stages of divisome assembly at midcell. As MinC oscillates toward these complexes, FtsZ oligomerization and bundling are inhibited, leading to shorter or monomeric FtsZ complexes, which become less visible by epifluorescence microscopy because of their rapid diffusion. Reconstitution of FtsZ-Min waves on lipid bilayers shows that FtsZ bundles partition away from high concentrations of MinC and that ZapA appears to protect FtsZ from MinC by inhibiting FtsZ turnover. A big issue in biology for the past 100 years has been that of how a cell finds its middle. In Escherichia coli, over 20 proteins assemble at the cell center at the time of division. We show that the MinCDE proteins, which prevent the formation of septa at the cell pole by inhibiting FtsZ, drive the counter-oscillation of early-cell-division proteins ZapA, ZapB, and ZipA, along with FtsZ. We propose that FtsZ forms filaments at the pole where the MinC concentration is the lowest and acts as a scaffold for binding of ZapA, ZapB, and ZipA: such complexes are disassembled by MinC and reform within the MinC oscillation period before accumulating at the cell center at the time of division. The ability of FtsZ to be targeted to the cell center in the form of oligomers bound by ZipA and ZapAB may facilitate the early stages of divisome assembly.