title: Septal localization of FtsQ, an essential cell division protein in Escherichia coli.
abstract: Septation in Escherichia coli requires several gene products. One of these, FtsQ, is a simple bitopic membrane protein with a short cytoplasmic N terminus, a membrane-spanning segment, and a periplasmic domain. We have constructed a merodiploid strain that expresses both FtsQ and the fusion protein green fluorescent protein (GFP)-FtsQ from single-copy chromosomal genes. The gfp-ftsQ gene complements a null mutation in ftsQ. Fluorescence microscopy revealed that GFP-FtsQ localizes to the division site. Replacing the cytoplasmic and transmembrane domains of FtsQ with alternative membrane anchors did not prevent the localization of the GFP fusion protein, while replacing the periplasmic domain did, suggesting that the periplasmic domain is necessary and sufficient for septal targeting. GFP-FtsQ localization to the septum depended on the cell division proteins FtsZ and FtsA, which are cytoplasmic, but not on FtsL and FtsI, which are bitopic membrane proteins with comparatively large periplasmic domains. In addition, the septal localization of ZipA apparently did not require functional FtsQ. Our results indicate that FtsQ is an intermediate recruit to the division site.
authors.affiliation: Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: J C
authors.initials: JC
authors.lastname: Chen
authors.forename: D S
authors.initials: DS
authors.lastname: Weiss
authors.forename: J M
authors.initials: JM
authors.lastname: Ghigo
authors.forename: J
authors.initials: J
authors.lastname: Beckwith
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division; D004171:Diploidy; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029968:Escherichia coli Proteins; D005816:Genetic Complementation Test; D005819:Genetic Markers; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D016296:Mutagenesis; D011993:Recombinant Fusion Proteins / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C068023:FtsQ protein, E coli; D005819:Genetic Markers; D008164:Luminescent Proteins; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins