title: Characterization of a complex chemosensory signal transduction system which controls twitching motility in Pseudomonas aeruginosa.
abstract: Virulence of the opportunistic pathogen Pseudomonas aeruginosa involves the coordinate expression of a wide range of virulence factors including type IV pili which are required for colonization of host tissues and are associated with a form of surface translocation termed twitching motility. Twitching motility in P. aeruginosa is controlled by a complex signal transduction pathway which shares many modules in common with chemosensory systems controlling flagella rotation in bacteria and which is composed, in part, of the previously described proteins PilG, PilH, PilI, PilJ and PilK. Here we describe another three components of this pathway: ChpA, ChpB and ChpC, as well as two downstream genes, ChpD and ChpE, which may also be involved. The central component of the pathway, ChpA, possesses nine potential sites of phosphorylation: six histidine-containing phosphotransfer (HPt) domains, two novel serine- and threonine-containing phosphotransfer (SPt, TPt) domains and a CheY-like receiver domain at its C-terminus, and as such represents one of the most complex signalling proteins yet described in nature. We show that the Chp chemosensory system controls twitching motility and type IV pili biogenesis through control of pili assembly and/or retraction as well as expression of the pilin subunit gene pilA. The Chp system is also required for full virulence in a mouse model of acute pneumonia.
authors.affiliation: ARC Special Research Centre for Functional and Applied Genomics, Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD 4072, Australia.
authors.forename: Cynthia B
authors.initials: CB
authors.lastname: Whitchurch
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Leech
authors.forename: Michael D
authors.initials: MD
authors.lastname: Young
authors.forename: Derek
authors.initials: D
authors.lastname: Kennedy
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Sargent
authors.forename: Jacob J
authors.initials: JJ
authors.lastname: Bertrand
authors.forename: Annalese B T
authors.initials: AB
authors.lastname: Semmler
authors.forename: Albert S
authors.initials: AS
authors.lastname: Mellick
authors.forename: Paul R
authors.initials: PR
authors.lastname: Martin
authors.forename: Richard A
authors.initials: RA
authors.lastname: Alm
authors.forename: Matthew
authors.initials: M
authors.lastname: Hobbs
authors.forename: Scott A
authors.initials: SA
authors.lastname: Beatson
authors.forename: Bixing
authors.initials: B
authors.lastname: Huang
authors.forename: Lam
authors.initials: L
authors.lastname: Nguyen
authors.forename: James C
authors.initials: JC
authors.lastname: Commolli
authors.forename: Joanne N
authors.initials: JN
authors.lastname: Engel
authors.forename: Aldis
authors.initials: A
authors.lastname: Darzins
authors.forename: John S
authors.initials: JS
authors.lastname: Mattick
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism / Q000382:microbiology; D036781:Fimbriae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010861:Fimbriae, Bacterial / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009068:Movement; D005810:Multigene Family; D011550:Pseudomonas aeruginosa / Q000166:cytology / Q000472:pathogenicity / Q000502:physiology*; D016415:Sequence Alignment; D015398:Signal Transduction; D037521:Virulence Factors / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D037521:Virulence Factors; D036781:Fimbriae Proteins