Dataset Information

Tir Is Essential for the Recruitment of Tks5 to Enteropathogenic Escherichia coli Pedestals.

ABSTRACT: Enteropathogenic Escherichia coli (EPEC) is a bacterial pathogen that infects the epithelial lining of the small intestine and causes diarrhea. Upon attachment to the intestinal epithelium, EPEC uses a Type III Secretion System to inject its own high affinity receptor Translocated intimin receptor (Tir) into the host cell. Tir facilitates tight adhesion and recruitment of actin-regulating proteins leading to formation of an actin pedestal beneath the infecting bacterium. The pedestal has several similarities with podosomes, which are basolateral actin-rich extensions found in some migrating animal cells. Formation of podosomes is dependent upon the early podosome-specific scavenger protein Tks5, which is involved in actin recruitment. Although Tks5 is expressed in epithelial cells, and podosomes and EPEC pedestals share many components in their structure and mechanism of formation, the potential role of Tks5 in EPEC infections has not been studied. The aim of this study was to determine the subcellular localization of Tks5 in epithelial cells and to investigate if Tks5 is recruited to the EPEC pedestal. In an epithelial MDCK cell line stably expressing Tks5-EGFP, Tks5 localized to actin bundles. Upon infection, EPEC recruited Tks5-EGFP. Tir, but not Tir phosphorylation was essential for the recruitment. Time-lapse microscopy revealed that Tks5-EGFP was recruited instantly upon EPEC attachment to host cells, simultaneously with actin and N-WASp. EPEC infection of cells expressing a ?PX-Tks5 deletion version of Tks5 showed that EPEC was able to both infect and form pedestals when the PX domain was deleted from Tks5. Future investigations will clarify the role of Tks5 in EPEC infection and pedestal formation.

SUBMITTER: Jensen HH

PROVIDER: S-EPMC4633291 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Tir Is Essential for the Recruitment of Tks5 to Enteropathogenic Escherichia coli Pedestals.

Jensen Helene H HH Pedersen Hans N HN Stenkjær Eva E Pedersen Gitte A GA Login Frédéric H FH Nejsum Lene N LN

PloS one 20151104 11

Enteropathogenic Escherichia coli (EPEC) is a bacterial pathogen that infects the epithelial lining of the small intestine and causes diarrhea. Upon attachment to the intestinal epithelium, EPEC uses a Type III Secretion System to inject its own high affinity receptor Translocated intimin receptor (Tir) into the host cell. Tir facilitates tight adhesion and recruitment of actin-regulating proteins leading to formation of an actin pedestal beneath the infecting bacterium. The pedestal has several ...[more]

PMID: 26536015

Similar Datasets

Project description:Attaching and effacing (A/E) rabbit enteropathogenic Escherichia coli (REPEC) strains belonging to serogroup O103 are an important cause of diarrhea in weaned rabbits. Like human EPEC strains, they possess the locus of enterocyte effacement clustering the genes involved in the formation of the A/E lesions. In addition, pathogenic REPEC O103 strains produce an Esp-dependent but Eae (intimin)-independent alteration of the host cell cytoskeleton characterized by the formation of focal adhesion complexes and the reorganization of the actin cytoskeleton into bundles of stress fibers. To investigate the role of intimin and its translocated coreceptor (Tir) in the pathogenicity of REPEC, we have used a newly constructed isogenic tir null mutant together with a previously described eae null mutant. When human HeLa epithelial cells were infected, the tir mutant was still able to induce the formation of stress fibers as previously reported for the eae null mutant. When the rabbit epithelial cell line RK13 was used, REPEC O103 produced a classical fluorescent actin staining (FAS) effect, whereas both the eae and tir mutants were FAS negative. In a rabbit ligated ileal loop model, neither mutant was able to induce A/E lesions. In contrast to the parental strain, which intimately adhered to the enterocytes and destroyed the brush border microvilli, bacteria of both mutants were clustered in the mucus without reaching and damaging the microvilli. The role of intimin and Tir was then analyzed in vivo by oral inoculation of weaned rabbits. Although both mutants were still present in the intestinal flora of the rabbits 3 weeks after oral inoculation, neither mutant strain induced any clinical signs or significant weight loss in the inoculated rabbits whereas the parental strain caused the death of 90% of the inoculated rabbits. Nevertheless, an inflammatory infiltrate was present in the lamina propria of the rabbits infected with both mutants, with an inflammatory response greater for the eae null mutant. In conclusion, we have confirmed the role of intimin in virulence, and we have shown, for the first time, that Tir is also a key factor in vivo for pathogenicity.

Project description:BackgroundEnteropathogenic (EPEC) and enterohaemorrhagic (EHEC) Escherichia coli are responsible for food poisoning (enteritis and enterotoxaemia) in humans in developed countries. Cattle are considered to be an important reservoir of EHEC and EPEC strains for humans. Moreover, some of the strains, belonging to the O26, O111, O118 serogroups, for example, are also responsible for digestive disorders in calves. The Translocated intimin receptor (Tir), the intimin (Eae) and the Tir-cytoskeleton coupling protein (TccP) represent three virulence factors implicated in the intimate attachment of the bacteria to the eukaryotic cell. Major variants have already been described for these genes among the different serogroups but minor variations have not often been studied. In this study, we examined the polymorphisms of the tir, eae and tccP2 genes of O26 strains (EPEC and EHEC isolated from bovines and from humans) with the aim to determine whether these polymorphisms are host specific or not.ResultsOf the 70 tested strains, 10 strains (14% of the strains) presented one or several polymorphisms in the tir and eae genes, which have never previously been described. Concerning tccP2 detection, 47 of the 70 strains (67% of the strains) were found to be positive for this gene. Most of the strains were found to possess tccP2 variants described in strains of serogroup O26. Nevertheless, three strains had tccP2 genes respectively described in strains of serogroup O111, O103 and O55. Moreover, none of the polymorphisms was statistically specific to the bovine or the human isolates. Nevertheless, the two major variants of tccP2 were statistically associated with the pathotype (EPEC or EHEC).ConclusionsIn conclusion, tir and eae gene polymorphisms were found not to be numerous and not to be predominantly synonymous. Moreover, no difference was observed between human and bovine strains regarding the presence of polymorphisms. Finally, some tccP2 variants appeared to be pathotype specific. Further investigations need to be performed on a larger number of strains in order to confirm this specificity.

Dataset Information

Tir Is Essential for the Recruitment of Tks5 to Enteropathogenic Escherichia coli Pedestals.

Publications

Tir Is Essential for the Recruitment of Tks5 to Enteropathogenic Escherichia coli Pedestals.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets