Topological regulation of cell division in Escherichia coli involves rapidpole to pole oscillation of the division inhibitor MinC under the control of MinD and MinE

Placement of the Z ring at midcell in Escherichia coil is assured by the ac tion of the min system, which blocks usage of potential division sites that exist at the cell poles. This activity of min is achieved through the acti on of an inhibitor of division, MinC, that is activated by MinD and topolog ically regulated by MinE. In this study, we have used a functional GFP-MinC fusion to monitor the location of MinC, We find that GFP-MinC is a cytopla smic protein in the absence of the other Min proteins. The addition of MinD , a peripheral membrane protein that interacts with MinC, results in GFP-Mi nC appearing on the membrane. In the presence of both MinD and MinE, GFP-Mi nC oscillates rapidly between the halves of the cell. Thus, MinC is positio ned by the other Min products, but in a dynamic manner so that it is in pos ition to inhibit Z ring assembly away from midcell.