Fig. 1. Division site placement in E. coli. (A) At the polar zone of the cell, MinD-ATP (circle) associates with the inner membrane and recruits MinC (oval), to create a zone of inhibition of FtsZ polymerisation (broken arrow). MinE (diamond) associates with MinD at the leading edge of the polar zone and stimulates MinD ATPase activity, leading to the release of phosphate (P_i). MinD-ADP is released from the membrane and the MinCD inhibition complex subsequently relocates to the opposite pole of the cell (B). The process is repeated and oscillation of the Min proteins from pole to pole of the cell results in formation of the Z-ring at the cell midpoint (C) and subsequent symmetric cell division (D).