Vecchiarelli Anthony G, Li Min, Mizuuchi Michiyo, Mizuuchi Kiyoshi
Laboratory of Molecular Biology, National Institute of Diabetes, and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
Mol Microbiol. 2014 Aug;93(3):453-63. doi: 10.1111/mmi.12669. Epub 2014 Jul 1.
The E. coli Min system forms a cell-pole-to-cell-pole oscillator that positions the divisome at mid-cell. The MinD ATPase binds the membrane and recruits the cell division inhibitor MinC. MinE interacts with and releases MinD (and MinC) from the membrane. The chase of MinD by MinE creates the in vivo oscillator that maintains a low level of the division inhibitor at mid-cell. In vitro reconstitution and visualization of Min proteins on a supported lipid bilayer has provided significant advances in understanding Min patterns in vivo. Here we studied the effects of flow, lipid composition, and salt concentration on Min patterning. Flow and no-flow conditions both supported Min protein patterns with somewhat different characteristics. Without flow, MinD and MinE formed spiraling waves. MinD and, to a greater extent MinE, have stronger affinities for anionic phospholipid. MinD-independent binding of MinE to anionic lipid resulted in slower and narrower waves. MinE binding to the bilayer was also more susceptible to changes in ionic strength than MinD. We find that modulating protein diffusion with flow, or membrane binding affinities with changes in lipid composition or salt concentration, can differentially affect the retention time of MinD and MinE, leading to spatiotemporal changes in Min patterning.
大肠杆菌Min系统形成一个从细胞一极到另一极的振荡器，将分裂体定位在细胞中部。MinD ATP酶结合细胞膜并募集细胞分裂抑制剂MinC。MinE与MinD（以及MinC）相互作用并使其从细胞膜上释放。MinE对MinD的追逐形成了体内振荡器，该振荡器在细胞中部维持低水平的分裂抑制剂。在支持脂质双分子层上对Min蛋白进行体外重建和可视化，在理解体内Min模式方面取得了重大进展。在这里，我们研究了流动、脂质组成和盐浓度对Min模式形成的影响。流动和不流动条件均支持具有不同特征的Min蛋白模式。在不流动的情况下，MinD和MinE形成螺旋波。MinD以及在更大程度上MinE对阴离子磷脂具有更强的亲和力。MinE与阴离子脂质的MinD非依赖性结合导致波更缓慢且更窄。与MinD相比，MinE与双分子层的结合对离子强度变化也更敏感。我们发现，通过流动调节蛋白质扩散，或通过改变脂质组成或盐浓度调节膜结合亲和力，可以不同程度地影响MinD和MinE的保留时间，从而导致Min模式形成的时空变化。
