title: Two different Pseudomonas aeruginosa chemosensory signal transduction complexes localize to cell poles and form and remould in stationary phase.
abstract: Pseudomonas aeruginosa has sets of sensory genes designated che and che2. The che genes are required for flagella-mediated chemotaxis. The che2 genes are expressed in the stationary phase of growth and are probably also involved in flagella-mediated behavioural responses. P. aeruginosa also has 26 chemoreceptor genes, six of which are preferentially expressed in stationary phase. Subcellular localization experiments indicated that Che proteins form signal transduction complexes at cell poles throughout growth. Cyan fluorescent protein (CFP)-tagged McpA, a stationary phase-expressed chemoreceptor, appeared and colocalized with yellow fluorescent protein (YFP)-tagged CheA when cells entered stationary phase. This indicates that P. aeruginosa chemotaxis protein complexes are subject to remoulding by chemoreceptor proteins that are expressed when cells stop growing. CheA-CFP and CheY2-YFP tagged proteins that were coexpressed in the same cell had separate subcellular locations, indicating that Che2 proteins do not enter into direct physical interactions with Che proteins. Che2 protein complex formation required McpB, another stationary phase induced chemoreceptor that is predicted to be soluble. This implies that Che2 complexes have a function that depends on just one chemoreceptor. Our results suggest that motile P. aeruginosa cells have signal transduction systems that are adapted to allow non-growing cells to sense and respond to their environment differently from actively growing cells.
authors.affiliation: Department of Microbiology, University of Washington, Seattle, WA 98195, USA.
authors.forename: Zehra Tüzün
authors.initials: ZT
authors.lastname: Güvener
authors.forename: Delia F
authors.initials: DF
authors.lastname: Tifrea
authors.forename: Caroline S
authors.initials: CS
authors.lastname: Harwood
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D002455:Cell Division / Q000235:genetics / Q000502:physiology; D002633:Chemotaxis / Q000235:genetics / Q000502:physiology; D005407:Flagella / Q000378:metabolism / Q000502:physiology; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D000072236:Methyl-Accepting Chemotaxis Proteins; D008856:Microscopy, Fluorescence; D008957:Models, Genetic; D009876:Operon / Q000235:genetics; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics* / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; C485182:Cyan Fluorescent Protein; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins