Identification and characterisation of a novel adhesin Ifp in Yersinia pseudotuberculosis

Abstract

BackgroundIn order to identify new virulence determinants in Y. pseudotuberculosis a comparison between its genome and that of Yersinia pestis was undertaken. This reveals dozens of pseudogenes in Y. pestis, which are still putatively functional in Y. pseudotuberculosis and may be important in the enteric lifestyle. One such gene, YPTB1572 in the Y. pseudotuberculosis IP32953 genome sequence, encodes a protein with similarity to invasin, a classic adhesion/invasion protein, and to intimin, the attaching and effacing protein from enteropathogenic (EPEC) and enterohaemorraghic (EHEC) Escherichia coli.ResultsWe termed YPTB1572 Ifp (Intimin family protein) and show that it is able to bind directly to human HEp-2 epithelial cells. Cysteine and tryptophan residues in the C-terminal region of intimin that are essential for function in EPEC and EHEC are conserved in Ifp. Protein binding occurred at distinct foci on the HEp-2 cell surface and can be disrupted by mutation of a single cysteine residue at the C-terminus of the protein. Temporal expression analysis using lux reporter constructs revealed that ifp is expressed at late log phase at 37°C in contrast to invasin, suggesting that Ifp is a late stage adhesin. An ifp defined mutant showed a reduction in adhesion to HEp-2 cells and was attenuated in the Galleria mellonella infection model.ConclusionA new Y. pseudotuberculosis adhesin has been identified and characterised. This Ifp is a new member in the family of invasin/intimin outer membrane adhesins.

The invasin D protein from Yersinia pseudotuberculosis selectively binds the Fab region of host antibodies and affects colonization of the intestine

“…We next reasoned that a host protein represents the target of InvD, in analogy to InvA. Usually, the adhesion domain in the invasin-family represents the domain that targets a specific host molecule and mediates interaction with the host cell during infection (18,19). Due to the low structural similarity of the adhesion domain of InvD to known proteins, we expected the adhesion domain to bind a novel, yet unidentified molecule.…”

“…InvB was reported to support colonization of the host lymphatic tissues and organs (18,19). InvC promoted adhesion to intestinal cells, but its loss did significantly affect survival of infected mice (18,19). We recently reported the structure of InvE (20), but further details regarding the specific function of InvE as well as of InvD remain elusive.…”

“…The interaction between InvA and β1 integrins activates actin rearrangement resulting in the internalization of bacteria (16,17). In addition to InvA, four additional invasins InvB (lfp), InvC, InvD and InvE have been identified in Y. pseudotuberculosis (18)(19)(20). InvB was reported to support colonization of the host lymphatic tissues and organs (18,19).…”

“…In addition to InvA, four additional invasins InvB (lfp), InvC, InvD and InvE have been identified in Y. pseudotuberculosis (18)(19)(20). InvB was reported to support colonization of the host lymphatic tissues and organs (18,19). InvC promoted adhesion to intestinal cells, but its loss did significantly affect survival of infected mice (18,19).…”

Identification of host factors required for Yersinia pestis macrophage intracellular survival and their impact on vacuole maturation, acidification and trafficking.

“…The first screen monitored changes in yopE transcription with a PyopE::luxAB reporter [157], while the second used a lux operon driven by a constitutive promoter to monitor bacterial growth [158]. Other groups have engineered luxCDABE reporters to be under the transcription control of promoters of virulence genes to monitor expression patterns of these genes [159][160][161]. In addition to these in vitro assays, a limited number of studies in Yersinia using bioluminescent reporters for optical imaging of whole animals have been reported.…”