The Min System[edit]
One model of Z-ring formation permits its formation only after a certain spatial signal that tells the cell that it is big enough to divide.[12] FtsZ polymerization is closely linked to the Min family of proteins, which were all discovered as E. coli mutants that could not produce a properly localized septum.[13] The Min proteins, which must prevent the FtsZ ring from being placed anywhere near the mid cell and nuclear material, are hypothesized to be involved in a spatial regulatory mechanism that links size increases prior to cell division to FtsZ polymerization in the middle of the cell.