Condensation of FtsZ filaments can drive bacterial cell division
Condensation of FtsZ filaments can drive bacterial cell division
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DOI：
10.1073/pnas.0807963106
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发表时间：
2009-01-06
影响因子：
11.1
通讯作者：
Sun, Sean X.
中科院分区：
文献类型：
--
作者：
Lan, Ganhui;Daniels, Brian R.;Sun, Sean X.
力在生物系统中对于实现关键细胞功能（例如运动性、细胞器运输和细胞分裂）是重要的。目前，已知的力产生机制通常涉及马达蛋白。在细菌细胞中，没有已知的马达蛋白参与细胞分裂。相反，分割环（Z环）主要由FtsZ、FtsA和ZipA组成，用于施加收缩力。细菌细胞分裂中力产生的机制尚不清楚。使用计算模型，我们表明，Z-环的形成结果从共定位的FtsZ和FtsA介导的有利对齐的FtsZ聚合物。该模型预测，Z-环经历了从低密度状态到高密度状态的凝聚转变，并产生足够的收缩力来实现分裂。FtsZ GTP水解促进缩合过渡期间的单体周转，但不直接产生力。体内荧光测量表明，FtsZ密度增加分裂过程中，在雅阁的结果。该机制类似于气液凝聚的货车德瓦尔斯图，并表明生物体可以利用微相变产生机械力。
Forces are important in biological systems for accomplishing key cell functions, such as motility, organelle transport, and cell division. Currently, known force generation mechanisms typically involve motor proteins. In bacterial cells, no known motor proteins are involved in cell division. Instead, a division ring (Z-ring) consists of mostly FtsZ, FtsA, and ZipA is used to exerting a contractile force. The mechanism of force generation in bacterial cell division is unknown. Using computational modeling, we show that Z-ring formation results from the colocalization of FtsZ and FtsA mediated by the favorable alignment of FtsZ polymers. The model predicts that the Z-ring undergoes a condensation transition from a lowdensity state to a high-density state and generates a sufficient contractile force to achieve division. FtsZ GTP hydrolysis facilitates monomer turnover during the condensation transition, but does not directly generate forces. In vivo fluorescence measurements show that FtsZ density increases during division, in accord with model results. The mechanism is akin to van der Waals picture of gas-liquid condensation, and shows that organisms can exploit microphase transitions to generate mechanical forces.