Disruption of divisome assembly rescued by FtsN–FtsA interaction in Escherichia coli

Significance Cell division inEscherichia coli requires 12 essential proteins that assemble into the divisome in a sequential manner. Assembly starts with formation of the Z-ring and culminates with the arrival of FtsN, which triggers septal peptidoglycan synthesis. Normally, deletion of any of these 12 proteins disrupts divisome assembly and results in a division block. However, about half of these proteins can be bypassed under some conditions, raising a question of how the divisome assembles under such conditions. Here we show that these bypasses require the interaction of FtsA with FtsN and that this normally weak interaction is enhanced under these conditions, leading to the back-recruitment of the other divisome proteins to the Z-ring.