A physical and functional interaction between Escherichia coli FtsK and topoisomerase IV
A physical and functional interaction between Escherichia coli FtsK and topoisomerase IV
复制标题
DOI：
10.1074/jbc.m308926200
复制
发表时间：
2003-11-07
影响因子：
4.8
通讯作者：
Marians, KJ
中科院分区：
文献类型：
--
作者：
Espeli, O;Lee, C;Marians, KJ
FtsK和拓扑异构酶（Topo） IV都参与大肠杆菌的染色体分离。前一种蛋白质位于隔环，是染色体二聚体分解所必需的。后一种蛋白质是染色体十核酸酶。我们最近证明，Topo IV活性在细胞周期后期集中在类核的间隔近端区域。在这里，我们证明了FtsK和Topo IV在物理和功能上相互作用。Topo IV在FtsK免疫沉淀中被回收。双杂交分析和免疫印迹分析表明，这种相互作用是由Topo IV的ParC亚基介导的。此外，我们发现FtsK的c端马达结构域刺激Topo IV的十烷化活性，但不刺激细胞中另一种II型拓扑异构酶DNA回转酶的十烷化活性。Topo IV和FtsK似乎也在细胞中合作。通过过量产生DnaX来挽救parE温度敏感突变，从而导致温度敏感的Topo IV的稳定，这需要FtsK和dif的c端结构域，而通过过量产生Topo III来挽救，绕过Topo IV的功能，不需要。FtsK和Topo IV之间的相互作用可能提供了一种将Topo IV酶集中在细胞中心的方法。
FtsK and topoisomerase (Topo) IV are both involved in chromosome segregation in Escherichia coli. The former protein resides at the septal ring and is required for resolution of chromosome dimers. The latter protein is the chromosomal decatenase. We have demonstrated recently that Topo IV activity is concentrated at the septal proximal regions of the nucleoids late in the cell cycle. Here we demonstrate that FtsK and Topo IV physically and functionally interact. Topo IV was recovered in immunoprecipitates of FtsK. Two-hybrid analysis and immunoblotting showed that this interaction was mediated by the ParC subunit of Topo IV. In addition, we show that the C-terminal motor domain of FtsK stimulates the decatenation activity of Topo IV but not that of DNA gyrase, the other type II topoisomerase in the cell. Topo IV and FtsK appear to cooperate in the cell as well. Rescue of a parE temperature-sensitive mutation by overproduction of DnaX, which leads to stabilization of the temperature-sensitive Topo IV, required both the C-terminal domain of FtsK and dif, whereas rescue by overproduction of Topo III, which bypasses Topo IV function, did not. The interaction between FtsK and Topo IV may provide a means for concentrating the latter enzyme at the cell center.