Distribution of espM and espT among enteropathogenic and enterohaemorrhagic Escherichia coli

Arbeloa, Ana; Blanco, Miguel; Moreira, Fabiana C.; Bulgin, Richard; López, Cecilia; Dahbi, Ghizlane; Blanco, Jesús E.; Mora, Azucena; Alonso, Marı́a Pilar; Mamani, Rosalía; Gomes, Tânia A. T.; Blanco, Jorge; Frankel, Gad

doi:10.1099/jmm.0.010231-0

Cited by 29 publications

(28 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…S1), has shown that the gene is present in ca. 1.8% of the tested strains [21]. In order to investigate the role of EspT in cell invasion we selected to use the espT positive strains E110019 and C. rodentum ; the espT negative EPEC, strain JPN15 [38], was used as a control.…”

Section: Resultsmentioning

confidence: 99%

The T3SS Effector EspT Defines a New Category of Invasive Enteropathogenic E. coli (EPEC) Which Form Intracellular Actin Pedestals

et al. 2009

Self Cite

View full text Add to dashboard Cite

Enteropathogenic Escherichia coli (EPEC) strains are defined as extracellular pathogens which nucleate actin rich pedestal-like membrane extensions on intestinal enterocytes to which they intimately adhere. EPEC infection is mediated by type III secretion system effectors, which modulate host cell signaling. Recently we have shown that the WxxxE effector EspT activates Rac1 and Cdc42 leading to formation of membrane ruffles and lamellipodia. Here we report that EspT-induced membrane ruffles facilitate EPEC invasion into non-phagocytic cells in a process involving Rac1 and Wave2. Internalized EPEC resides within a vacuole and Tir is localized to the vacuolar membrane, resulting in actin polymerization and formation of intracellular pedestals. To the best of our knowledge this is the first time a pathogen has been shown to induce formation of actin comets across a vacuole membrane. Moreover, our data breaks the dogma of EPEC as an extracellular pathogen and defines a new category of invasive EPEC.

show abstract

Section: Resultsmentioning

confidence: 99%

The T3SS Effector EspT Defines a New Category of Invasive Enteropathogenic E. coli (EPEC) Which Form Intracellular Actin Pedestals

et al. 2009

Self Cite

View full text Add to dashboard Cite

show abstract

“…In another study, IpgB1 was described to drive Rac1 and Cdc42 activation (19). In addition, more recently identified family members such as EspM and EspT have been interpreted to activate rather than mimic RhoA and Rac1/Cdc42, respectively (20,21), which was recently verified in the case of EspM2 (22). The finding that the WXXXE protein SifA displays a fold similar to the bacterial GEF SopE (15,23) provided the first structural evidence for WXXXE proteins acting as GEFs.…”

mentioning

confidence: 87%

Structure of Shigella IpgB2 in Complex with Human RhoA

Klink

Barden

Heidler

et al. 2010

Journal of Biological Chemistry

View full text Add to dashboard Cite

A common theme in bacterial pathogenesis is the manipulation of eukaryotic cells by targeting the cytoskeleton. This is in most cases achieved either by modifying actin, or indirectly via activation of key regulators controlling actin dynamics such as Rho-GTPases. A novel group of bacterial virulence factors termed the WXXXE family has emerged as guanine nucleotide exchange factors (GEFs) for these GTPases. The precise mechanism of nucleotide exchange, however, has remained unclear. Here we report the structure of the WXXXE-protein IpgB2 from Shigella flexneri and its complex with human RhoA. We unambiguously identify IpgB2 as a bacterial RhoA-GEF and dissect the molecular mechanism of GDP release, an essential prerequisite for GTP binding. Our observations uncover that IpgB2 induces conformational changes on RhoA mimicking DbI-but not DOCK family GEFs. We also show that dissociation of the GDP⅐Mg 2؉ complex is preceded by the displacement of the metal ion to the ␣-phosphate of the nucleotide, diminishing its affinity to the GTPase. These data refine our understanding of the mode of action not only of WXXXE GEFs but also of mammalian GEFs of the DH/PH family.Remodeling of the actin cytoskeleton is essential for eukaryotic life, taking place in processes as diverse as division, motility, or cell-cell communication. The actin cytoskeleton is composed of actin monomers and helical filaments constantly assembling and disassembling at their ends, which is tightly regulated by multiple signaling pathways employing hundreds of actin-binding proteins. Most if not all signaling pathways converge on small GTPases of the Rho family, which are long recognized as key signaling switches inducing different actin filament structures (1-3). As effector interaction occurs in the GTP-bound state, their intrinsic GTPase activity is counterbalanced by guanine nucleotide exchange factors (GEFs) 2 driving GTP re-loading by increasing the intrinsic nucleotide dissociation rate (4). Activation of the name-giving family member RhoA induces cell contraction. This drives the formation of stress fiber bundles and focal adhesions in fibroblasts or endothelial cells, exerting force onto the substratum or neighboring cells (5). In neurons for instance, RhoA activation induces growth cone retraction (6). Other Rho family members trigger the formation of cell protrusions antagonistic to RhoA, with Rac1 and Cdc42 inducing lamellipodia and filopodia, respectively (7,8).Given their importance in cell physiology, Rho-GTPases have also emerged as key targets of pathogens modifying cell signaling or actin remodeling for their own needs (9). For instance, multiple bacterial toxins inhibiting RhoA, such as C3 exoenzyme of Clostridium botulinum, have served as invaluable tools to study RhoA function in vivo (10, 11). As an alternative to inhibition, Rho-GTPase signaling pathways driving different types of actin reorganization are also frequently bypassed or activated by pathogens, at least transiently, allowing them to induce their tight adherence to or ...

show abstract

“…In addition, the Nle effectors Ibe (invasion of endothelial cells) and EspT have been originally described and characterized in aEPEC strains 102, 103. Ibe appears to regulate Tir phosphorylation and to enhance actin polymerization and pedestal formation, 103 while EspT 104 modulates actin dynamics, leading to membrane ruffling and cell invasion, and induces macrophages to produce interleukins IL-8 and IL-1β and PGE2 102 …”

Section: Typical and Atypical Enteropathogenic E Colimentioning

confidence: 99%

Diarrheagenic Escherichia coli

Gomes

Elias

Scaletsky

et al. 2016

Brazilian Journal of Microbiology

412

353

View full text Add to dashboard Cite

Most Escherichia coli strains live harmlessly in the intestines and rarely cause disease in healthy individuals. Nonetheless, a number of pathogenic strains can cause diarrhea or extraintestinal diseases both in healthy and immunocompromised individuals. Diarrheal illnesses are a severe public health problem and a major cause of morbidity and mortality in infants and young children, especially in developing countries. E. coli strains that cause diarrhea have evolved by acquiring, through horizontal gene transfer, a particular set of characteristics that have successfully persisted in the host. According to the group of virulence determinants acquired, specific combinations were formed determining the currently known E. coli pathotypes, which are collectively known as diarrheagenic E. coli. In this review, we have gathered information on current definitions, serotypes, lineages, virulence mechanisms, epidemiology, and diagnosis of the major diarrheagenic E. coli pathotypes.

show abstract

Distribution of espM and espT among enteropathogenic and enterohaemorrhagic Escherichia coli

Cited by 29 publications

References 33 publications

The T3SS Effector EspT Defines a New Category of Invasive Enteropathogenic E. coli (EPEC) Which Form Intracellular Actin Pedestals

The T3SS Effector EspT Defines a New Category of Invasive Enteropathogenic E. coli (EPEC) Which Form Intracellular Actin Pedestals

Structure of Shigella IpgB2 in Complex with Human RhoA

Diarrheagenic Escherichia coli

Contact Info

Product

Resources

About