PMID:15916962
| Citation |
Bernhardt, TG and de Boer, PA (2005) SlmA, a nucleoid-associated, FtsZ binding protein required for blocking septal ring assembly over Chromosomes in E. coli. Mol. Cell 18:555-64 |
|---|---|
| Abstract |
Cell division in Escherichia coli begins with assembly of the tubulin-like FtsZ protein into a ring structure just underneath the cell membrane. Spatial control over Z ring assembly is achieved by two partially redundant negative regulatory systems, the Min system and nucleoid occlusion (NO), which cooperate to position the division site at midcell. In contrast to the well-studied Min system, almost nothing is known about how Z ring assembly is blocked in the vicinity of nucleoids to effect NO. Reasoning that Min function might become essential in cells impaired for NO, we screened for mutations synthetically lethal with a defective Min system (slm mutants). By using this approach, we identified SlmA (Ttk) as the first NO factor in E. coli. Our combined genetic, cytological, and biochemical results suggest that SlmA is a DNA-associated division inhibitor that is directly involved in preventing Z ring assembly on portions of the membrane surrounding the nucleoid. |
| Links |
PubMed Online version:10.1016/j.molcel.2005.04.012 |
| Keywords |
Carrier Proteins/genetics; Carrier Proteins/metabolism; Cell Division/physiology; Cell Membrane/metabolism; Chromosomes, Bacterial; DNA Mutational Analysis; Escherichia coli/cytology; Escherichia coli/genetics; Escherichia coli/metabolism; Escherichia coli Proteins/genetics; Escherichia coli Proteins/metabolism; Recombinant Fusion Proteins/genetics; Recombinant Fusion Proteins/metabolism |
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Significance
This paper describes both the slmA- and the slmA-minCDE- mutant phenotypes. The double mutant's synthetically lethal phenotype is suppressed by 1.)growth in minimal media, and 2.) mild overexpression of the FtsZ protein. In the absence of the slmA and min proteins, Z rings form throughout filamented cells, but do not constrict. It is suggested that the critical concentration of FtsZ molecules is not reached in the filament and this is why the rings do not constrict. Also, the DNA binding ability of the HTH motif was investigated and it was concluded that SlmA localizes to the DNA using this motif. The paper utilizes a light scattering technique to conclude that SlmA interacts with FtsZ directly in vitro.
Useful Materials and Methods
This paper describes the use of light scattering to identify in vitro interactions b/t SlmA and FtsZ.
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