title: The type II secretion system and its ubiquitous lipoprotein substrate, SslE, are required for biofilm formation and virulence of enteropathogenic Escherichia coli.
abstract: Enteropathogenic Escherichia coli (EPEC) is a major cause of diarrhea in infants in developing countries. We have identified a functional type II secretion system (T2SS) in EPEC that is homologous to the pathway responsible for the secretion of heat-labile enterotoxin by enterotoxigenic E. coli. The wild-type EPEC T2SS was able to secrete a heat-labile enterotoxin reporter, but an isogenic T2SS mutant could not. We showed that the major substrate of the T2SS in EPEC is SslE, an outer membrane lipoprotein (formerly known as YghJ), and that a functional T2SS is essential for biofilm formation by EPEC. T2SS and SslE mutants were arrested at the microcolony stage of biofilm formation, suggesting that the T2SS is involved in the development of mature biofilms and that SslE is a dominant effector of biofilm development. Moreover, the T2SS was required for virulence, as infection of rabbits with a rabbit-specific EPEC strain carrying a mutation in either the T2SS or SslE resulted in significantly reduced intestinal colonization and milder disease.
authors.affiliation: Department of Microbiology and Immunology, The University of Melbourne, Melbourne, Australia.
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Baldi
authors.forename: Ellen E
authors.initials: EE
authors.lastname: Higginson
authors.forename: Dianna M
authors.initials: DM
authors.lastname: Hocking
authors.forename: Judyta
authors.initials: J
authors.lastname: Praszkier
authors.forename: Rosalia
authors.initials: R
authors.lastname: Cavaliere
authors.forename: Catherine E
authors.initials: CE
authors.lastname: James
authors.forename: Vicki
authors.initials: V
authors.lastname: Bennett-Wood
authors.forename: Kristy I
authors.initials: KI
authors.lastname: Azzopardi
authors.forename: Lynne
authors.initials: L
authors.lastname: Turnbull
authors.forename: Trevor
authors.initials: T
authors.lastname: Lithgow
authors.forename: Roy M
authors.initials: RM
authors.lastname: Robins-Browne
authors.forename: Cynthia B
authors.initials: CB
authors.lastname: Whitchurch
authors.forename: Marija
authors.initials: M
authors.lastname: Tauschek
mesh_terms: D000818:Animals; D018441:Biofilms / Q000254:growth & development*; D002462:Cell Membrane; D054308:Enteropathogenic Escherichia coli / Q000166:cytology / Q000235:genetics / Q000472:pathogenicity* / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D009154:Mutation; D011817:Rabbits; D013379:Substrate Specificity; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; C583861:SslE protein, E coli; D037521:Virulence Factors