A Polymer Model Explains MinDE Dynamics in E. coli Cell Division

In Escherichia coli, the location of the site for cell division is regulated by the action of the Min proteins. These proteins undergo a periodic pole-to-pole oscillation that involves polymerization and ATPase activity of MinD under the controlling influence of MinE. This oscillation suppresses division near the poles while permitting division at midcell. Here, we propose a polymer model for MinD and MinE dynamics that is motivated by recent fluorescence, biochemical and genetic studies. The model quantitatively agrees with the experimentally observed dynamics in wild-type cells as well as a large set of mutant phenotypes, providing explanations for several phenotypes that have never been addressed by previous modeling attempts. Finally, the model emphasizes the importance of non-equilibrium polymer dynamics in cell function by demonstrating how behavior analogous to the dynamic instability of microtubules is used by E. coli MinD to achieve a sufficiently rapid time scale in controlling division site selection.