Assembly dynamics of FtsZ rings in Bacillus subtilis and Escherichia coli and effects of FtsZ-regulating proteins.
FtsZ is the major cytoskeletal component of the bacterial cell division machinery. It forms a ring-shaped structure (the Z ring) that constricts as the bacterium divides. Previous in vivo experiments with green fluorescent protein-labeled FtsZ and fluorescence recovery after photobleaching have shown that the Escherichia coli Z ring is extremely dynamic, continually remodeling itself with a half time of 30 s, similar to microtubules in the mitotic spindle. In the present work, under different experimental conditions, we have found that the half time for fluorescence recovery of E. coli Z rings is even shorter (approximately 9 s). As before, the turnover appears to be coupled to GTP hydrolysis, since the mutant FtsZ84 protein, with reduced GTPase in vitro, showed an approximately 3-fold longer half time. We have also extended the studies to Bacillus subtilis and found that this species exhibits equally rapid dynamics of the Z ring (half time, approximately 8 s). Interestingly, null mutations of the FtsZ-regulating proteins ZapA, EzrA, and MinCD had only modest effects on the assembly dynamics. This suggests that these proteins do not directly regulate FtsZ subunit exchange in and out of polymers. In B. subtilis, only 30 to 35% of the FtsZ protein was in the Z ring, from which we conclude that a Z ring only 2 or 3 protofilaments thick can function for cell division.
Department of Cell Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.
David E
DE
Anderson
Frederico J
FJ
Gueiros-Filho
Harold P
HP
Erickson
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D019677:Artificial Gene Fusion; D001412:Bacillus subtilis / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division / Q000502:physiology; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005453:Fluorescence; D020558:GTP Phosphohydrolases / Q000378:metabolism; D017353:Gene Deletion; D005798:Genes, Bacterial; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D006160:Guanosine Triphosphate / Q000378:metabolism; D006207:Half-Life; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation
D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins; D029968:Escherichia coli Proteins; C121014:EzrA protein, Bacillus subtilis; C071525:FtsZ protein, Bacteria; C076835:FtsZ84 protein, E coli; D008164:Luminescent Proteins; D008565:Membrane Proteins; C080466:MinC protein, Bacteria; C462942:MinC protein, E coli; D049452:Green Fluorescent Proteins; D006160:Guanosine Triphosphate; D000251:Adenosine Triphosphatases; D020558:GTP Phosphohydrolases; C072069:MinD protein, E coli