Assembly dynamics of FtsZ rings in Bacillus subtilis and Escherichia coli and effects of FtsZ-regulating proteins
Assembly dynamics of FtsZ rings in Bacillus subtilis and Escherichia coli and effects of FtsZ-regulating proteins
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DOI：
10.1128/jb.186.17.5775-5781.2004
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发表时间：
2004-09-01
影响因子：
3.2
通讯作者：
Erickson, HP
中科院分区：
文献类型：
--
作者：
Anderson, DE;Gueiros-Filho, FJ;Erickson, HP
FtsZ是细菌细胞分裂机制的主要细胞骨架成分。它形成一个环状结构（Z形环），在细菌分裂时收缩。先前用绿色荧光蛋白标记的FtsZ进行的体内实验和光漂白后的荧光恢复实验表明，大肠杆菌Z环是非常动态的，它以30秒的半周期不断地自我重塑，类似于有丝分裂纺锤体中的微管。在本工作中，在不同的实验条件下，我们发现大肠杆菌Z环的荧光恢复半时间甚至更短（类似于9秒）。与之前一样，这种转换似乎与GTP水解有关，因为突变体FtsZ84蛋白在体外GTP酶减少的情况下，显示出类似于3倍长的半期。我们还将研究扩展到枯草芽孢杆菌，发现该物种表现出同样快速的Z环动力学（半时间，类似于8秒）。有趣的是，ftsz调节蛋白ZapA、EzrA和MinCD的零突变对组装动力学只有轻微的影响。这表明这些蛋白并不直接调节FtsZ亚基在聚合物内外的交换。在枯草芽孢杆菌中，只有30 ~ 35%的FtsZ蛋白位于Z环中，由此我们可以推断，只有2 ~ 3根原丝粗的Z环可以发挥细胞分裂的作用。
FtsZ is the major cytoskeletal component of the bacterial cell division machinery. It forms a ring-shaped structure (the Z ring) that constricts as the bacterium divides. Previous in vivo experiments with green fluorescent protein-labeled FtsZ and fluorescence recovery after photobleaching have shown that the Escherichia coli Z ring is extremely dynamic, continually remodeling itself with a half time of 30 s, similar to microtubules in the mitotic spindle. In the present work, under different experimental conditions, we have found that the half time for fluorescence recovery of E. coli Z rings is even shorter (similar to9 s). As before, the turnover appears to be coupled to GTP hydrolysis, since the mutant FtsZ84 protein, with reduced GTPase in vitro, showed an similar to3-fold longer half time. We have also extended the studies to Bacillus subtilis and found that this species exhibits equally rapid dynamics of the Z ring (half time, similar to8 s). Interestingly, null mutations of the FtsZ-regulating proteins ZapA, EzrA, and MinCD had only modest effects on the assembly dynamics. This suggests that these proteins do not directly regulate FtsZ subunit exchange in and out of polymers. In B. subtilis, only 30 to 35% of the FtsZ protein was in the Z ring, from which we conclude that a Z ring only 2 or 3 protofilaments thick can function for cell division.