Cell division in Escherichia coli: role of FtsL domains in septal localization, function, and oligomerization.
In Escherichia coli, nine essential cell division proteins are known to localize to the division septum. FtsL is a 13-kDa bitopic membrane protein with a short cytoplasmic N-terminal domain, a membrane-spanning segment, and a periplasmic domain that has a repeated heptad motif characteristic of leucine zippers. Here, we identify the requirements for FtsL septal localization and function. We used green fluorescent protein fusions to FtsL proteins where domains of FtsL had been exchanged with analogous domains from either its Haemophilus influenzae homologue or the unrelated MalF protein to show that both the membrane-spanning segment and the periplasmic domain of FtsL are required for localization to the division site. Mutagenesis of the periplasmic heptad repeat motif severely impaired both localization and function as well as the ability of FtsL to drive the formation of sodium dodecyl sulfate-resistant multimers in vitro. These results are consistent with the predicted propensity of the FtsL periplasmic domain to adopt a coiled-coiled structure. This coiled-coil motif is conserved in all gram-negative and gram-positive FtsL homologues identified so far. Our data suggest that most of the FtsL molecule is a helical coiled coil involved in FtsL multimerization.
Ghigo
J M
JM
Unité des Membranes Bactériennes, Institut Pasteur (CNRS URA 1300), 75724 Paris Cedex 15, France. jmghigo@pasteur.fr
Beckwith
J
J
D018528:ATP-Binding Cassette Transporters; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D018797:Cell Cycle Proteins; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002462:Cell Membrane / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D004926:Escherichia coli / Q000166:cytology* / Q000187:drug effects / Q000235:genetics*; D029968:Escherichia coli Proteins; D006193:Haemophilus influenzae / Q000235:genetics; D058619:Maltose-Binding Proteins; D008565:Membrane Proteins / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins; D019897:Periplasm / Q000378:metabolism; D033902:Periplasmic Binding Proteins; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology
D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D029968:Escherichia coli Proteins; C461619:MalE protein, E coli; D058619:Maltose-Binding Proteins; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; D033902:Periplasmic Binding Proteins; D011993:Recombinant Fusion Proteins; C078387:ftsL protein, E coli; C461599:maltose transport system, E coli; D012967:Sodium Dodecyl Sulfate