Corbin Goodman Lauren C, Erickson Harold P
Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA.
Department of Cell Biology, Duke University, Durham, North Carolina, USA.
Microbiology (Reading). 2022 Jun;168(6). doi: 10.1099/mic.0.001194.
There has been recent debate as to the source of constriction force during cell division. FtsZ can generate a constriction force on tubular membranes , suggesting it may generate the constriction force . However, another study showed that mutants of FtsZ did not affect the rate of constriction, whereas mutants of the PG assembly did, suggesting that PG assembly may push the constriction from the outside. Supporting this model, two groups found that cells that have initiated constriction can complete septation while the Z ring is poisoned with the FtsZ targeting antibiotic PC190723. PC19 arrests treadmilling but leaves FtsZ in place. We sought to determine if a fully assembled Z ring is necessary during constriction. To do this, we used a temperature-sensitive FtsZ mutant, FtsZ84. FtsZ84 supports cell division at 30 °C, but it disassembles from the Z ring within 1 min upon a temperature jump to 42 °C. Following the temperature jump we found that cells in early constriction stop constricting. Cells that had progressed to the later stage of division finished constriction without a Z ring. These results show that in , an assembled Z ring is essential for constriction except in the final stage, contradicting the simplest interpretation of previous studies using PC19.
最近关于细胞分裂过程中收缩力的来源存在争议。FtsZ 可在管状膜上产生收缩力，这表明它可能产生收缩力。然而，另一项研究表明，FtsZ 的突变体并不影响收缩速率，而肽聚糖（PG）组装的突变体则会影响，这表明 PG 组装可能从外部推动收缩。支持该模型的是，两组研究人员发现，已经开始收缩的细胞在 Z 环被靶向 FtsZ 的抗生素 PC190723 毒害时仍能完成隔膜形成。PC19 阻止了踏车行为，但使 FtsZ 留在原位。我们试图确定在收缩过程中一个完全组装好的 Z 环是否是必需的。为此，我们使用了一种温度敏感的 FtsZ 突变体 FtsZ84。FtsZ84 在 30°C 时支持细胞分裂，但在温度跃升至 42°C 后 1 分钟内会从 Z 环上解离。温度跃升后，我们发现处于早期收缩阶段的细胞停止收缩。已经进入分裂后期的细胞在没有 Z 环的情况下完成了收缩。这些结果表明，在[具体情况未提及]中，除了在最后阶段，一个组装好的 Z 环对于收缩是必不可少的，这与之前使用 PC19 的研究的最简单解释相矛盾。
