Minimization of the Bacillus subtilis divisome suggests FtsZ and SepF can form an active Z-ring, and reveals the amino acid transporter BraB as a new cell division influencing factor.

Bacterial cytokinesis begins with polymerization of the tubulin homologue FtsZ into a ring-like structure at midcell, the Z-ring, which recruits the late cell division proteins that synthesize the division septum. Assembly of FtsZ is carefully regulated and supported by a dozen conserved cell division proteins. Generally, these proteins are not essential, but removing more than one is in many cases lethal.

Control of septum thickness by the curvature of SepF polymers.

Gram-positive bacteria divide by forming a thick cross wall. How the thickness of this septal wall is controlled is unknown. In this type of bacteria, the key cell division protein FtsZ is anchored to the cell membrane by two proteins, FtsA and/or SepF.