FtsZ assembles the bacterial cell division machinery by a diffusion-and-capture mechanism

The mechanism of bacterial cell division is largely unknown. The protein machinery performing cell division is organized by FtsZ, a tubulin-homolog that forms treadmilling filaments at the cell division site. Treadmilling is thought to actively move proteins around the cell thereby distributing peptidoglycan synthesis to make two new cell poles. To understand this process, we reconstituted part of the bacterial cell division machinery using the purified components FtsZ, FtsA and truncated transmembrane proteins essential for cell division. We found that membrane-bound cytosolic peptides of FtsN and FtsQ co-migrated with treadmilling FtsZ-FtsA filaments. Remarkably, rather than moving in a directed fashion, individual peptides followed FtsZ filaments by a diffusion-and-capture mechanism. Our work provides a mechanism for how the Z-ring dynamically recruits divisome proteins and highlights the importance of transient interactions for the self-organization of complex biological structures. We propose that this mechanism is used more widely to organize and transmit spatiotemporal information in living cells. One Sentence Summary FtsZ treadmilling assembles bacterial division machinery by diffusion-and-capture mechanism.