Fu X, Shih Y L, Zhang Y, Rothfield L I
Department of Microbiology, University of Connecticut Health Center, Farmington, CT 06030, USA.
Proc Natl Acad Sci U S A. 2001 Jan 30;98(3):980-5. doi: 10.1073/pnas.98.3.980. Epub 2001 Jan 23.
Placement of the division site at midcell in Escherichia coli requires the MinE protein. MinE acts by imparting topological specificity to the MinCD division inhibitor, preventing the inhibitor from acting at the midcell site while permitting it to block division at other unwanted sites along the length of the cell. It was previously shown that MinE assembled into a ring structure that appeared to be localized near midcell, apparently explaining the ability of MinE to specifically counteract MinCD at midcell. We report here that the MinE ring is not fixed in position near midcell but is a dynamic structure that undergoes a repetitive cycle of movement first to one cell pole and then to the opposite pole. Taken together with studies of the dynamic behavior of the MinD protein, the results suggest that the topological specificity of division site placement may not involve a localized action of MinE to counteract the MinCD division inhibitor at midcell but rather the ability of MinE to move the division inhibitor away from midcell and to the cell poles.
在大肠杆菌中，细胞分裂位点定位于细胞中部需要MinE蛋白。MinE通过赋予MinCD分裂抑制剂拓扑特异性来发挥作用，阻止该抑制剂在细胞中部起作用，同时允许它在细胞长度方向上的其他不需要的位点阻断分裂。先前的研究表明，MinE组装成一个似乎定位于细胞中部附近的环状结构，这显然解释了MinE在细胞中部特异性对抗MinCD的能力。我们在此报告，MinE环并非固定在细胞中部附近的位置，而是一个动态结构，经历先向一个细胞极移动，然后再向相反极移动的重复循环。结合对MinD蛋白动态行为的研究，结果表明，分裂位点定位的拓扑特异性可能并不涉及MinE在细胞中部对抗MinCD分裂抑制剂的局部作用，而是MinE将分裂抑制剂从细胞中部移至细胞极的能力。
