title: Membrane insertion of the bacterial signal transduction protein ToxR and requirements of transcription activation studied by modular replacement of different protein substructures.
abstract: The Vibrio cholerae protein ToxR is an integral membrane protein that acts as a transcription activator in response to environmental signals; it controls expression of toxin genes ctxA and ctxB, along with a variety of other genes related to pathogenicity. Here it is shown that: (i) ToxR has a modular architecture and that activation of transcription starting at the ctx promoter depends strictly on dimerization of the periplasmic ToxR domain; (ii) the transmembrane (TM) region of ToxR is sufficient as a topogenic signal but not for stable membrane anchoring of the protein; (iii) the TM region has no special function in signal transduction and (iv) a proline residue located within the TM region minimizes background transcription activation, most plausibly by reducing TM-TM interaction. Possible applications of ToxR as a technical tool for analysing protein-protein interactions between pairs of arbitrary TM domains are discussed.
authors.affiliation: Institut für Molekulare Genetik, George-August-Universität Göttingen, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Kolmar
authors.forename: F
authors.initials: F
authors.lastname: Hennecke
authors.forename: K
authors.initials: K
authors.lastname: Götze
authors.forename: B
authors.initials: B
authors.lastname: Janzer
authors.forename: B
authors.initials: B
authors.lastname: Vogt
authors.forename: F
authors.initials: F
authors.lastname: Mayer
authors.forename: H J
authors.initials: HJ
authors.lastname: Fritz
mesh_terms: D018528:ATP-Binding Cassette Transporters; D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics; D002772:Cholera Toxin / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D005656:Fungal Proteins / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics; D058619:Maltose-Binding Proteins; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins; D033902:Periplasmic Binding Proteins; D011392:Proline / Q000502:physiology; D011401:Promoter Regions, Genetic / Q000235:genetics; D011487:Protein Conformation; D011494:Protein Kinases / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D015398:Signal Transduction / Q000502:physiology*; D014157:Transcription Factors / Q000737:chemistry* / Q000235:genetics; D015533:Transcriptional Activation / Q000502:physiology*; D014734:Vibrio cholerae / Q000235:genetics*
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D005656:Fungal 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; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C461599:maltose transport system, E coli; C499324:toxR protein, Vibrio cholerae; C066719:toxR protein, bacteria; D002772:Cholera Toxin; D011392:Proline; D011494:Protein Kinases