In Escherichia coli FtsZ assembles into a Z ring at midcell while assembly at polar sites is prevented by the min system. MinC, a component of this system, is an inhibitor of FtsZ assembly that is positioned within the cell by interaction with MinDE. MinC is an oligomer, probably a dimer. The C terminal half of MinC is the most conserved and interacts with MinD. The N terminal half is thought interact with FtsZ.