A hypothesis to explain division site selection in Escherichia coli by combining nucleoid occlusion and Min.
The positioning of the site of cell division in Escherichia coli results, it is generally believed, from the operation of nucleoid occlusion in combination with the Min system. Nucleoid occlusion prevents division over the nucleoids and directs it by default to the mid-cell region between segregating nucleoids or to polar regions while the Min system prevents division in polar regions. Unresolved questions include how these systems interact to control the earliest known event in division, the assembly at the membrane of the tubulin-like protein, FtsZ, and, more importantly, what exactly constitutes a division site. Evidence exists that (1) the coupled transcription, translation and insertion of proteins into membrane (transertion), can structure the cytoplasmic membrane into phospholipid domains, (2) the MinD protein can convert vesicles into tubes and (3) a variety of membranous structures can be observed at mid-cell. These data support a model in which transertion from the segregating daughter chromosomes leads to the formation of a distinct proteolipid domain between them at mid-cell; the composition of this domain allows phospholipid tubes to extend like fingers into the cytoplasm; these tubes then become the substrate for the dynamic assembly and disassembly of FtsZ which converts them into the invaginating fold responsible for division; the Min system inhibits division at unwanted sites and times by removing these tubes especially at the cell poles.
Norris
Vic
V
Assemblages Moléculaires: Modélisation et Imagerie SIMS, FRE CNRS 2829, Faculté des Sciences and Techniques, Université de Rouen, 76821 Mont-Saint-Aignan, France. vjn@univ-rouen.fr
Woldringh
Conrad
C
Mileykovskaya
Eugenia
E
D000251:Adenosine Triphosphatases / Q000378:metabolism / Q000502:physiology*; D001426:Bacterial Proteins / Q000378:metabolism; D018797:Cell Cycle Proteins; D002455:Cell Division; D002462:Cell Membrane / Q000502:physiology; D020090:Chromosome Segregation; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004926:Escherichia coli / Q000166:cytology*; D029968:Escherichia coli Proteins / Q000378:metabolism / Q000502:physiology*; D021962:Membrane Microdomains / Q000502:physiology; D008954:Models, Biological; D010743:Phospholipids
D001426:Bacterial Proteins; D018797:Cell Cycle Proteins; D003598:Cytoskeletal Proteins; D029968:Escherichia coli Proteins; C071525:FtsZ protein, Bacteria; C093548:MinE protein, E coli; D010743:Phospholipids; D000251:Adenosine Triphosphatases; C072069:MinD protein, E coli