The division inhibitor EzrA contains a seven-residue patch required for maintaining the dynamic nature of the medial FtsZ ring
The division inhibitor EzrA contains a seven-residue patch required for maintaining the dynamic nature of the medial FtsZ ring
复制标题
DOI：
10.1128/jb.01172-07
复制
发表时间：
2007-12-01
影响因子：
3.2
通讯作者：
Levin, Petra Anne
中科院分区：
文献类型：
--
作者：
Haeusser, Daniel P.;Garza, Anna Cristina;Levin, Petra Anne
必需的细胞骨架蛋白FtsZ在新生分裂位点组装成环状结构，并作为原核分裂机器组装的支架。我们以前的特点是EzrA作为抑制剂的FtsZ组装在枯草芽孢杆菌。EzrA直接与FtsZ相互作用，以防止异常FtsZ组装和细胞两极的胞质分裂。EzrA还以FtsZ依赖的方式集中在细胞动力学环，尽管其在该位置的确切作用尚不清楚。在这里，我们确定了一个保守的补丁的EzrA C端的氨基酸是必不可少的本地化的FtsZ环。该补丁中的突变（称为“QNR补丁”）消除EzrA定位到中间细胞，但不显著影响EzrA抑制FtsZ组装在细胞极的能力。ezrA QNR补丁突变细胞表现出稳定的FtsZ组装在中间细胞，并显着长于野生型细胞，尽管缺乏额外的FtsZ环。这些结果表明EzrA在体内具有两种不同的活性：（i）通过抑制从头FtsZ组装来防止细胞极处的异常FtsZ环形成，以及（ii）在内侧FtsZ环内维持适当的FtsZ组装动力学，从而使其对负责协调细胞生长和细胞分裂的因子敏感。
The essential cytoskeletal protein FtsZ assembles into a ring-like structure at the nascent division site and serves as a scaffold for the assembly of the prokaryotic division machinery. We previously characterized EzrA as an inhibitor of FtsZ assembly in Bacillus subtilis. EzrA interacts directly with FtsZ to prevent aberrant FtsZ assembly and cytokinesis at cell poles. EzrA also concentrates at the cytokinetic ring in an FtsZ-dependent manner, although its precise role at this position is not known. Here, we identified a conserved patch of amino acids in the EzrA C terminus that is essential for localization to the FtsZ ring. Mutations in this patch (designated the "QNR patch") abolish EzrA localization to midcell but do not significantly affect EzrA's ability to inhibit FtsZ assembly at cell poles. ezrA QNR patch mutant cells exhibit stabilized FtsZ assembly at midcell and are significantly longer than wild-type cells, despite lacking extra FtsZ rings. These results indicate that EzrA has two distinct activities in vivo: (i) preventing aberrant FtsZ ring formation at cell poles through inhibition of de novo FtsZ assembly and (ii) maintaining proper FtsZ assembly dynamics within the medial FtsZ ring, thereby rendering it sensitive to the factors responsible for coordinating cell growth and cell division.