Bacterial serine proteases secreted by the autotransporter pathway: classification, specificity, and role in virulence

Ruı́z-Pérez, Fernando; Nataro, James P.

doi:10.1007/s00018-013-1355-8

Cited by 132 publications

(182 citation statements)

References 165 publications

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“…The vacuolating AT toxin (Vat) of E. coli is a class II SPATE (34,36,45) that exhibits cytotoxicity to chicken embryonic fibroblast cells and contributes to avian cellulitis infection (46). The vat gene was originally identified within a pathogenicity island (PAI) designated the VAT-PAI from the avian pathogenic E. coli (APEC) strain Ec222 (46).…”

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confidence: 99%

Molecular Characterization of the Vacuolating Autotransporter Toxin in Uropathogenic Escherichia coli

et al. 2016

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The vacuolating autotransporter toxin (Vat) contributes to uropathogenic Escherichia coli (UPEC) fitness during systemic infection. Here, we characterized Vat and investigated its regulation in UPEC. We assessed the prevalence of vat in a collection of 45 UPEC urosepsis strains and showed that it was present in 31 (68%) of the isolates. The isolates containing the vat gene corresponded to three major E. coli sequence types (ST12, ST73, and ST95), and these strains secreted the Vat protein. Further analysis of the vat genomic locus identified a conserved gene located directly downstream of vat that encodes a putative MarR-like transcriptional regulator; we termed this gene vatX. The vat-vatX genes were present in the UPEC reference strain CFT073, and reverse transcriptase PCR (RT-PCR) revealed that the two genes are cotranscribed. Overexpression of vatX in CFT073 led to a 3-fold increase in vat gene transcription. The vat promoter region contained three putative nucleation sites for the global transcriptional regulator histone-like nucleoid structuring protein (H-NS); thus, the hns gene was mutated in CFT073 (to generate CFT073 hns). Western blot analysis using a Vat-specific antibody revealed a significant increase in Vat expression in CFT073 hns compared to that in wild-type CFT073. Direct H-NS binding to the vat promoter region was demonstrated using purified H-NS in combination with electrophoresis mobility shift assays. Finally, Vat-specific antibodies were detected in plasma samples from urosepsis patients infected by vat-containing UPEC strains, demonstrating that Vat is expressed during infection. Overall, this study has demonstrated that Vat is a highly prevalent and tightly regulated immunogenic serine protease autotransporter protein of Enterobacteriaceae (SPATE) secreted by UPEC during infection. IMPORTANCEUropathogenic Escherichia coli (UPEC) is the major cause of hospital-and community-acquired urinary tract infections. The vacuolating autotransporter toxin (Vat) is a cytotoxin known to contribute to UPEC fitness during murine sepsis infection. In this study, Vat was found to be highly conserved and prevalent among a collection of urosepsis clinical isolates and was expressed at human core body temperature. Regulation of vat was demonstrated to be directly repressed by the global transcriptional regulator H-NS and upregulated by the downstream gene vatX (encoding a new MarR-type transcriptional regulator). Additionally, increased Vat-specific IgG titers were detected in plasma from corresponding urosepsis patients infected with vatpositive isolates. Hence, Vat is a highly conserved and tightly regulated urosepsis-associated virulence factor. U rinary tract infections (UTIs) are one of the most common human infections, affecting 40 to 50% of women and approximately 12% of men globally (1). UTIs are ascending infections and can involve infection of the bladder (cystitis), kidneys (pyelonephritis), or dissemination into the bloodstream (urosepsis). Uropathogenic Escherichia coli (UPEC) strains ...

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confidence: 99%

Molecular Characterization of the Vacuolating Autotransporter Toxin in Uropathogenic Escherichia coli

et al. 2016

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“…Class I SPATE proteins exhibit cytotoxic effects on host cells, while class II SPATEs are primarily mucinases, with recent evidence indicating they also recognise and cleave host cell immunomodulating markers (Ruiz-Perez et al, 2011, Ayala-Lujan et al, 2014). An additional subdomain has also been described within class II SPATE passenger domains, known as domain 2 (Ruiz-Perez and Nataro, 2014b). Interestingly, domain 2 purified from the SPATE protein Hbp can bind calcium.…”

Section: Type V Secretion Pathwaymentioning

confidence: 99%

“…The first serine within this motif comprises the catalytic triad in conjunction with upstream conserved histidine and aspartate residues. SPATEs can be phylogenetically grouped into two classes (reviewed in Ruiz-Perez and Nataro, 2014a.…”

Section: Molecular Cloningmentioning

confidence: 99%

“…Class II SPATEs recognise a more diverse range of substrates including mucins (reviewed in , Ruiz-Perez and Nataro, 2014a and immunomodulatory host proteins (Ruiz-Perez et al, 2011).…”

Section: Molecular Cloningmentioning

confidence: 99%

“…The vacuolating AT toxin (Vat) of E. coli is a class II SPATE , Ruiz-Perez and Nataro, 2014a) that exhibits cytotoxicity to chicken embryonic fibroblast cells and contributes to avian cellulitis infection . The vat gene was originally identified within a pathogenicity island (Vat-PAI) from the avian pathogenic E. coli (APEC) strain Ec222 .…”

Section: Molecular Cloningmentioning

confidence: 99%

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Autotransporter proteins of Uropathogenic Escherichia coli: regulation, characterisation and the role of periplasmic proteins in their expression

Nichols¹

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Uropathogenic Escherichia coli (UPEC) are the primary cause for all urinary tract infections.Autotransporter (AT) proteins are virulence factors secreted by the type V secretion pathway. This project examined the prevalence, regulation and expression of the vacuolating AT toxin (Vat), and the role of periplasmic chaperone proteins in AT translocation.The vacuolating autotransporter (AT) toxin (Vat) contributes to Uropathogenic Escherichia coli (UPEC) fitness during systemic infection. Vat is a serine protease AT of Enterobacteriaceae (SPATE) with cytotoxic activity. Here we characterised Vat and investigated its regulation in UPEC.We assessed the prevalence of vat in a collection of 45 UPEC urosepsis strains and showed it that was present in 31 (68%) of the isolates. The isolates containing the vat gene corresponded to three major E. coli sequence types (ST12, 73 and 95) and these strains secreted the Vat protein.Further analysis of the vat genetic locus identified a conserved gene located directly downstream of vat that encodes a putative MarR-like transcriptional regulator, which we termed vatX. The vatvatX genes were present in the UPEC reference strain CFT073 and RT-PCR revealed both genes are co-transcribed. Over-expression of vatX in CFT073 led to a 3-fold increase in vat gene transcription. The vat promoter region contained three putative nucleation sites for the global transcriptional regulator H-NS; thus the hns gene was mutated in CFT073 (to generate CFT073hns).Western blot analysis using a Vat-specific antibody revealed a significant increase in Vat expression in CFT073hns compared to wild-type CFT073. Direct H-NS binding to the vat promoter region was demonstrated using purified H-NS in combination with electrophoresis mobility shift assays. Finally, Vat-specific antibodies were detected in plasma samples from urosepsis patients iv Declaration by authorThis thesis is composed of my original work, and contains no material previously published or written by another person except where due reference has been made in the text. I have clearly stated the contribution by others to jointly-authored works that I have included in my thesis.

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Autotransporter Adhesins in Escherichia coli Pathogenesis

Ortiz

Subedi

et al. 2017

Proteomics

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Most bacteria produce adhesion molecules to facilitate the interaction with host cells and establish successful infections. An important group of bacterial adhesins belong to the autotransporter (AT) superfamily, the largest group of secreted and outer membrane proteins in Gram-negative bacteria. AT adhesins possess diverse functions that facilitate bacterial colonisation, survival and persistence, and as such are often associated with increased bacterial fitness and pathogenic potential. In this review, we will describe AIDA-I type AT adhesins, which comprise the biggest and most diverse group in the AT family. We will focus on Escherichia coli proteins and define general aspects of their biogenesis, distribution, structural properties and key roles in infection.

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Bacterial serine proteases secreted by the autotransporter pathway: classification, specificity, and role in virulence

Cited by 132 publications

References 165 publications

Molecular Characterization of the Vacuolating Autotransporter Toxin in Uropathogenic Escherichia coli

Molecular Characterization of the Vacuolating Autotransporter Toxin in Uropathogenic Escherichia coli

Autotransporter proteins of Uropathogenic Escherichia coli: regulation, characterisation and the role of periplasmic proteins in their expression

Autotransporter Adhesins in Escherichia coli Pathogenesis

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