Dynamic structures in Escherichia coli: Spontaneous formation of MinE rings and MinD polar zones

In Escherichia coli, division site selection is regulated in part by the Min-protein system. Oscillations of the Min proteins from pole to pole every ≈40 sec have been revealed by in vivo studies of GFP fusions. The dynamic oscillatory structures produced by the Min proteins, including a ring of MinE protein, compact polar zones of MinD, and zebra-striped oscillations in filamentous cells, remain unexplained. We show that the Min oscillations, including mutant phenotypes, can be accounted for by in vitro-observed interactions involving MinD and MinE, with a crucial role played by the rate of nucleotide exchange. Recent discoveries suggest that protein oscillations may play a general role in proper chromosome and plasmid partitioning.