InterPro domain: IPR000158

In bacteria, FtsZ [ 1 , 2 , 3 , 4 ] is an essential cell division protein involved in the initiation of this event. It assembles into a cytokinetic ring on the inner surface of the cytoplasmic membrane at the place where division will occur. The ring serves as a scaffold that is disassembled when septation is completed. FtsZ ring formation is initiated at a single site on one side of the bacterium and appears to grow bidirectionally. In Escherichia coli, MinCD IPR005526 , encoded by the MinB locus, form a complex which appears to block the formation of FtsZ rings at the cell poles, at the ancient mid cell division sites, whilst MinE, encoded at the same locus, specifically prevents the action of MinCD at mid cell.

FtsZ is a GTP binding protein with a GTPase activity. It undergoes GTP-dependent polymerisation into filaments (or tubules) that seem to form a cytoskeleton involved in septum synthesis. The structure and the properties of FtsZ clearly provide it with the capacity for the cytoskeletal, perhaps motor role, necessary for "contraction" along the division plane. In addition, however, the FtsZ ring structure provides the framework for the recruitment or assembly of the ten or so membrane and cytoplasmic proteins, uniquely required for cell division in E. coli or Bacillus subtilis, some of which are required for biogenesis of the new hemispherical poles of the two daughter cells. FtsZ can polymerise into various structures, for example a single linear polymer of FtsZ monomers, called a protofilament. Protofilaments can associate laterally to form pairs (sometimes called thick filaments), bundles (ill-defined linear associations of multiple protofilaments) or thick filaments, sheets (parallel or anti-parallel two-dimensional associations of thick filaments) and tubes (anti-parallel associations of thick filaments in a circular fashion to form a tubular structure). In addition, small circles of FtsZ monomers (a short protofilament bent around to join itself, apparently head to tail) have been observed and termed mini-rings.

FtsZ is a protein of about 400 residues which is well conserved across bacterial species and which is also present in the chloroplast of plants [ 5 ] as well as in archaebacteria [ 6 ]. FtsZ is a homologue of eukaryotic tubulin with which it shows structural similarity.

1. FtsZ ring in bacterial cytokinesis. Mol. Microbiol. 9, 403-9
2. FtsZ, a prokaryotic homolog of tubulin? Cell 80, 367-70
3. The tubulin ancestor, FtsZ, draughtsman, designer and driving force for bacterial cytokinesis. J. Mol. Biol. 318, 219-36
4. GTPase activity of mycobacterial FtsZ is impaired due to its transphosphorylation by the eukaryotic-type Ser/Thr kinase, PknA. J. Biol. Chem. 281, 40107-13
5. Conserved cell and organelle division. Nature 376, 473-4
6. Isolation of an ftsZ homolog from the archaebacterium Halobacterium salinarium: implications for the evolution of FtsZ and tubulin. J. Bacteriol. 178, 1320-7