title: A predicted ABC transporter, FtsEX, is needed for cell division in Escherichia coli.
abstract: FtsE and FtsX have homology to the ABC transporter superfamily of proteins and appear to be widely conserved among bacteria. Early work implicated FtsEX in cell division in Escherichia coli, but this was subsequently challenged, in part because the division defects in ftsEX mutants are often salt remedial. Strain RG60 has an ftsE::kan null mutation that is polar onto ftsX. RG60 is mildly filamentous when grown in standard Luria-Bertani medium (LB), which contains 1% NaCl, but upon shift to LB with no NaCl growth and division stop. We found that FtsN localizes to potential division sites, albeit poorly, in RG60 grown in LB with 1% NaCl. We also found that in wild-type E. coli both FtsE and FtsX localize to the division site. Localization of FtsX was studied in detail and appeared to require FtsZ, FtsA, and ZipA, but not the downstream division proteins FtsK, FtsQ, FtsL, and FtsI. Consistent with this, in media lacking salt, FtsA and ZipA localized independently of FtsEX, but the downstream proteins did not. Finally, in the absence of salt, cells depleted of FtsEX stopped dividing before any change in growth rate (mass increase) was apparent. We conclude that FtsEX participates directly in the process of cell division and is important for assembly or stability of the septal ring, especially in salt-free media.
authors.affiliation: Department of Microbiology, University of Iowa, Iowa City, Iowa 52242, USA.
authors.forename: Kari L
authors.initials: KL
authors.lastname: Schmidt
authors.forename: Nicholas D
authors.initials: ND
authors.lastname: Peterson
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Kustusch
authors.forename: Mark C
authors.initials: MC
authors.lastname: Wissel
authors.forename: Becky
authors.initials: B
authors.lastname: Graham
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Phillips
authors.forename: David S
authors.initials: DS
authors.lastname: Weiss
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000032:analysis / Q000502:physiology*; D001426:Bacterial Proteins; D018797:Cell Cycle Proteins / Q000032:analysis / Q000502:physiology*; D002455:Cell Division; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000032:analysis / Q000502:physiology*; D004926:Escherichia coli / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000032:analysis / Q000502:physiology*; D021381:Protein Transport
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D018797:Cell Cycle Proteins; D029968:Escherichia coli Proteins; C491157:FtsX protein, E coli; C102286:FtsX protein, bacteria; C075980:FtsE protein, E coli; D019005:Cystic Fibrosis Transmembrane Conductance Regulator