Several other divisome components, the so-called early cell division proteins, are conjointly recruited with FtsZ. First, a tubulin homologue, FtsZ, polymerises into a cytoplasmic contractile ring structure, the Z-ring, at about 25–38% of the cell cycle 5, 6. In Escherichia coli, its different components are recruited to the division site in an almost linear pathway 5, 6. The bacterial divisome is a complex apparatus that contains over a dozen highly-conserved proteins 4. In bacteria, which lack a functional equivalent of the mitotic spindle, it is achieved by directing divisome assembly to the low DNA-density zone that develops at mid-cell between chromatid sisters when the concurrent replication and segregation of the chromosomes is sufficiently advanced 1, 2, 3. In eukaryotes, the necessary coordination between cell division and the replication/segregation cycle of the genetic material is achieved by coupling the assembly and activity of the division apparatus (the divisome) to the formation and activation of the mitotic spindle, the machinery that effects the simultaneous separation of sister chromosomes after replication. One of the most important rules imposed upon the process is that each daughter cell receives a complete copy of its mother’s genome. The propagation of life relies on the ability of cells to multiply by vegetative division. cholerae cells by limiting the accumulation of a cell pole marker, HubP, at the nascent cell poles. Our results further suggest that late assembly of the divisome probably helps maintain the asymmetric polar organisation of V. Thus, actual septation is restricted to a very short amount of time. In contrast, we present evidence suggesting that early pre-divisional Z-rings form between 40 and 50% of the cell cycle and mature into fully assembled divisome at about 80% of the cell cycle in Vibrio cholerae. Actual septation occupies most of the remaining half of the cell cycle.
#Pbp3 check compile size series#
The Z-ring serves as a scaffold for the recruitment of a second series of proteins, including integral membrane and periplasmic cell wall remodelling enzymes, at ~50% of the cell cycle. In the few model bacteria in which the division process was detailed, divisome assembly occurs in two distinct steps: a few proteins, including the FtsZ tubulin-like protein, form a membrane associated contractile ring, the Z-ring, at ~30% of the cell cycle. Bacterial cell division is a highly regulated process, which involves the formation of a complex apparatus, the divisome, by over a dozen proteins.