title: SlmA antagonism of FtsZ assembly employs a two-pronged mechanism like MinCD.
abstract: Assembly of the Z-ring over unsegregated nucleoids is prevented by a process called nucleoid occlusion (NO), which in Escherichia coli is partially mediated by SlmA. SlmA is a Z ring antagonist that is spatially regulated and activated by binding to specific DNA sequences (SlmA binding sites, SBSs) more abundant in the origin proximal region of the chromosome. However, the mechanism by which SBS bound SlmA (activated form) antagonizes Z ring assembly is controversial. Here, we report the isolation and characterization of two FtsZ mutants, FtsZ-K190V and FtsZ-D86N that confer resistance to activated SlmA. In trying to understand the basis of resistance of these mutants, we confirmed that activated SlmA antagonizes FtsZ polymerization and determined these mutants were resistant, even though they still bind SlmA. Investigation of SlmA binding to FtsZ revealed activated SlmA binds to the conserved C-terminal tail of FtsZ and that the ability of activated SlmA to antagonize FtsZ assembly required the presence of the tail. Together, these results lead to a model in which SlmA binding to an SBS is activated to bind the tail of FtsZ resulting in further interaction with FtsZ leading to depolymerization of FtsZ polymers. This model is strikingly similar to the model for the inhibitory mechanism of the spatial inhibitor MinCD.
authors: Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, United States of America.
authors: Shishen
authors: S
authors: Du
authors: Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, United States of America.
authors: Joe
authors: J
authors: Lutkenhaus
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism*; D001665:Binding Sites / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D002455:Cell Division / Q000235:genetics; D002876:Chromosomes, Bacterial; D003598:Cytoskeletal Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics; D009154:Mutation; D011485:Protein Binding; D055503:Protein Multimerization / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D029968:Escherichia coli Proteins; C071525:FtsZ protein, Bacteria; D008565:Membrane Proteins; C462942:MinC protein, E coli; C502032:SlmA protein, E coli; D000251:Adenosine Triphosphatases; C072069:MinD protein, E coli