title: Polar localization of a tripartite complex of the two-component system DcuS/DcuR and the transporter DctA in Escherichia coli depends on the sensor kinase DcuS.
abstract: The C4-dicarboxylate responsive sensor kinase DcuS of the DcuS/DcuR two-component system of E. coli is membrane-bound and reveals a polar localization. DcuS uses the C4-dicarboxylate transporter DctA as a co-regulator forming DctA/DcuS sensor units. Here it is shown by fluorescence microscopy with fusion proteins that DcuS has a dynamic and preferential polar localization, even at very low expression levels. Single assemblies of DcuS had high mobility in fast time lapse acquisitions, and fast recovery in FRAP experiments, excluding polar accumulation due to aggregation. DctA and DcuR fused to derivatives of the YFP protein are dispersed in the membrane or in the cytosol, respectively, when expressed without DcuS, but co-localize with DcuS when co-expressed at appropriate levels. Thus, DcuS is required for location of DctA and DcuR at the poles and formation of tripartite DctA/DcuS/DcuR sensor/regulator complexes. Vice versa, DctA, DcuR and the alternative succinate transporter DauA were not essential for polar localization of DcuS, suggesting that the polar trapping occurs by DcuS. Cardiolipin, the high curvature at the cell poles, and the cytoskeletal protein MreB were not required for polar localization. In contrast, polar localization of DcuS required the presence of the cytoplasmic PAS(C) and the kinase domains of DcuS.
authors.affiliation: Institute for Microbiology and Wine Research, University of Mainz, Mainz, Germany.
authors.forename: Patrick D
authors.initials: PD
authors.lastname: Scheu
authors.affiliation: Institute for Microbiology and Wine Research, University of Mainz, Mainz, Germany.
authors.forename: Philipp A
authors.initials: PA
authors.lastname: Steinmetz
authors.affiliation: Microbiology, Faculty for Biology, University of Freiburg, Freiburg, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Dempwolff
authors.affiliation: Microbiology, Faculty for Biology, University of Freiburg, Freiburg, Germany.
authors.forename: Peter L
authors.initials: PL
authors.lastname: Graumann
authors.affiliation: Institute for Microbiology and Wine Research, University of Mainz, Mainz, Germany.
authors.forename: Gottfried
authors.initials: G
authors.lastname: Unden
mesh_terms: D002308:Cardiolipins / Q000235:genetics / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D029382:Dicarboxylic Acid Transporters / Q000235:genetics / Q000378:metabolism*; D048168:Escherichia coli K12 / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D002308:Cardiolipins; D004268:DNA-Binding Proteins; C000589721:DctA protein, E coli; C115005:DcuR protein, E coli; D029382:Dicarboxylic Acid Transporters; D029968:Escherichia coli Proteins; D046912:Multiprotein Complexes; D014157:Transcription Factors; D011494:Protein Kinases; C469359:DcuS protein, E coli