Bacterial cell division

Formation of the bacterial division septum is catalyzed by a number of esse ntial proteins that assemble into a ring structure at the future division s ite. Assembly of proteins into the cytokinetic ring appears to occur in a h ierarchial order that is initiated by the FtsZ protein, a structural and fu nctional analog of eukaryotic tubulins. Placement of the division site at its correct location in Escherichia coli requires a division inhibitor (MinC), that is responsible for preventing se ptation at unwanted sites near the cell poles, and a topological specificit y protein (MinE), that forms a ring at midcell and protects the midcell sit e from the division inhibitor. However, the mechanism responsible for ident ifying the position of the midcell site or the polar sites used for spore s eptum formation is still unclear. Regulation of the division process and its coordination with other cell cyc le events, such as chromosome replication, are poorly understood. However, a protein has been identified in Caulobacter (CtrA) that regulates both the initiation of chromosome regulation and the transcription of ftsZ, and tha t may play an important role in the coordination process.