Yang Xinxing, Lyu Zhixin, Miguel Amanda, McQuillen Ryan, Huang Kerwyn Casey, Xiao Jie
Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.
Science. 2017 Feb 17;355(6326):744-747. doi: 10.1126/science.aak9995.
The bacterial tubulin FtsZ is the central component of the cell division machinery, coordinating an ensemble of proteins involved in septal cell wall synthesis to ensure successful constriction. How cells achieve this coordination is unknown. We found that in cells, FtsZ exhibits dynamic treadmilling predominantly determined by its guanosine triphosphatase activity. The treadmilling dynamics direct the processive movement of the septal cell wall synthesis machinery but do not limit the rate of septal synthesis. In FtsZ mutants with severely reduced treadmilling, the spatial distribution of septal synthesis and the molecular composition and ultrastructure of the septal cell wall were substantially altered. Thus, FtsZ treadmilling provides a mechanism for achieving uniform septal cell wall synthesis to enable correct polar morphology.
细菌微管蛋白FtsZ是细胞分裂机制的核心组成部分，它协调一系列参与隔膜细胞壁合成的蛋白质，以确保成功收缩。细胞如何实现这种协调尚不清楚。我们发现，在细胞中，FtsZ表现出动态踏车行为，主要由其鸟苷三磷酸酶活性决定。踏车行为动力学指导隔膜细胞壁合成机制的持续运动，但不限制隔膜合成的速率。在踏车行为严重降低的FtsZ突变体中，隔膜合成的空间分布以及隔膜细胞壁的分子组成和超微结构发生了显著改变。因此，FtsZ踏车行为提供了一种实现均匀隔膜细胞壁合成以形成正确极性形态的机制。
