The Dynamic Concentration Gradient of the Min System Coordinates with Cell Growth and Contributes to Cell Size

Pole-to-pole oscillation of the Min system mediates the cell division site placement that underlies the spatial and temporal organization of the Min proteins. This study reports dynamic modulation of the concentration gradient as the cell elongates, which is coupled with a near constant oscillation period under a given growth condition. The changing concentration gradient leads to gradual clearance of MinD at midcell, causing progressive relief from the inhibitory effect of the Min system on the assembly of the FtsZ ring. This concentration gradient differs among cells growing with different carbon sources or concentrations, which is in synchrony with the daughter cell sizes after division. The carbon stress responses of the MinD concentration gradient involve regulation by the sigma factor RpoS. Taken together, the results showed the plasticity of Min oscillation over the cell cycle that gradually sets up the assembly of the FtsZ ring.