In Vitro Reconstitution of the Initial Stages of the Bacterial Cell Division Machinery

Fission of many prokaryotes as well as some eukaryotic organelles depends on the self-assembly of the FtsZ protein into a membrane-associated ring structure early in the division process. Different components of the machinery are then sequentially recruited. Although the assembly order has been established, the molecular interactions and the understanding of the force-generating mechanism of this dividing machinery have remained elusive. It is desirable to develop simple reconstituted systems that attempt to reproduce, at least partially, some of the stages of the process. High-resolution studies of Escherichia coli FtsZ filaments' structure and dynamics on mica have allowed the identification of relevant interactions between filaments that suggest a mechanism by which the polymers could generate force on the membrane. Reconstituting the membrane-anchoring protein ZipA on E. coli lipid membrane on surfaces is now providing information on how the membrane attachment regulates FtsZ polymer dynamics and indicates the important role played by the lipid composition of the membrane.