Shiga toxin–binding site for host cell receptor GPP130 reveals unexpected divergence in toxin-trafficking mechanisms

Mukhopadhyay, Somshuvra; Redler, Brendan; Linstedt, Adam D.

doi:10.1091/mbc.e13-01-0057

Cited by 37 publications

(64 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The structural profiles and spatial orientations of the β4–β5 loops appear nearly identical (Figure A). However, STx2B does not bind GPP130, and this lack of binding has been ascribed to a lack of conserved residues in the β4–β5 loop (Figure B). In STx1B, residues H 78 and N 79 in the β4–β5 loop are required for GPP130 binding and endosome‐to‐Golgi transport , but the corresponding residues in STx2B are E 76 and S 77 (Figure B).…”

Section: Resultsmentioning

confidence: 99%

A Conserved Structural Motif Mediates Retrograde Trafficking of Shiga Toxin Types 1 and 2

Selyunin

Mukhopadhyay²

2015

Traffic

Self Cite

View full text Add to dashboard Cite

Shiga toxin-producing E. coli (STEC) produce two types of Shiga toxin (STx): STx1 and STx2. The toxin A-subunits block protein synthesis while the B-subunits mediate retrograde trafficking. STEC infections do not have definitive treatments, and there is growing interest in generating toxin transport inhibitors for therapy. However, a comprehensive understanding of the mechanisms of toxin trafficking is essential for drug development. While STx2 is more toxic in vivo, prior studies focused on STx1 B-subunit (STx1B) trafficking. Here, we show that, compared to STx1B, trafficking of the B-subunit of STx2 (STx2B) to the Golgi occurs with slower kinetics. Despite this difference, similar to STx1B, endosome-to-Golgi transport of STx2B does not involve transit through degradative late endosomes and is dependent on dynamin II, epsinR, retromer and syntaxin5. Importantly, additional experiments show that a surface-exposed loop in STx2B (β4-β5 loop) is required for its endosome-to-Golgi trafficking. We previously demonstrated that residues in the corresponding β4-β5 loop of STx1B are required for interaction with GPP130, the STx1B-specific endosomal receptor, and for endosome-to-Golgi transport. Overall, STx1B and STx2B share a common pathway and use a similar structural motif to traffic to the Golgi, suggesting that the underlying mechanisms of endosomal sorting may be evolutionarily conserved.

show abstract

Section: Resultsmentioning

confidence: 99%

A Conserved Structural Motif Mediates Retrograde Trafficking of Shiga Toxin Types 1 and 2

Selyunin

Mukhopadhyay²

2015

Traffic

Self Cite

View full text Add to dashboard Cite

show abstract

“…Hope that manganese could be used as a treatment for STEC infection diminished, however, when Gaston et al and additional work by Mukhopadhyay et al showed that the protective effects of manganese did not extend to Stx2 [65,66]. Gaston and colleagues also showed that manganese was more toxic, both in cultured cells and in mice, than was reported by Mukhopadhyay and Linstedt.…”

Section: Discussionmentioning

confidence: 99%

Zinc protects against shiga-toxigenic Escherichia coli by acting on host tissues as well as on bacteria

et al. 2014

View full text Add to dashboard Cite

BackgroundZinc supplements can treat or prevent enteric infections and diarrheal disease. Many articles on zinc in bacteria, however, highlight the essential nature of this metal for bacterial growth and virulence, suggesting that zinc should make infections worse, not better. To address this paradox, we tested whether zinc might have protective effects on intestinal epithelium as well as on the pathogen.ResultsUsing polarized monolayers of T84 cells we found that zinc protected against damage induced by hydrogen peroxide, as measured by trans-epithelial electrical resistance. Zinc also reduced peroxide-induced translocation of Shiga toxin (Stx) across T84 monolayers from the apical to basolateral side. Zinc was superior to other divalent metals to (iron, manganese, and nickel) in protecting against peroxide-induced epithelial damage, while copper also showed a protective effect.The SOS bacterial stress response pathway is a powerful regulator of Stx production in STEC. We examined whether zinc’s known inhibitory effects on Stx might be mediated by blocking the SOS response. Zinc reduced expression of recA, a reliable marker of the SOS. Zinc was more potent and more efficacious than other metals tested in inhibiting recA expression induced by hydrogen peroxide, xanthine oxidase, or the antibiotic ciprofloxacin. The close correlation between zinc’s effects on recA/SOS and on Stx suggested that inhibition of the SOS response is one mechanism by which zinc protects against STEC infection.ConclusionsZinc’s ability to protect against enteric bacterial pathogens may be the result of its combined effects on host tissues as well as inhibition of virulence in some pathogens. Research focused solely on the effects of zinc on pathogenic microbes may give an incomplete picture by failing to account for protective effects of zinc on host epithelia.

show abstract

“…While ␤-lactamase confers antibiotic resistance, Shiga toxin 2 subunit B and the serine protease autotransporters are important for E. coli O104:H4 virulence. Subunit B of Shiga toxin 2 allows holotoxin surface attachment and retrograde transport into host cells (39). The O104:H4 AAF/1 major fimbrial subunit and a fimbrial chaperone protein, FimC, were also abundant in the growth medium.…”

Section: Detection Of Proteins From Minimal Mediummentioning

confidence: 99%

Different Cellular Origins and Functions of Extracellular Proteins from Escherichia coli O157:H7 and O104:H4 as Determined by Comparative Proteomic Analysis

Islam

Nagy

Garrett

et al. 2016

Appl Environ Microbiol

View full text Add to dashboard Cite

Extracellular proteins play important roles in bacterial interactions with the environmental matrices. In this study, we examined the extracellular proteins from Escherichia coli O157:H7 and O104:H4 by tandem mass spectrometry. We identified 500 and 859 proteins from the growth media of E. coli O157:H7 and O104:H4, respectively, including 371 proteins common to both strains. Among proteins that were considered specific to E. coli O157:H7 or present at higher relative abundances in O157:H7 medium, most (57 of 65) had secretion signal sequences in their encoding genes. Noticeably, the proteins included locus of enterocyte effacement (LEE) virulence factors, proteins required for peptidyl-lipoprotein accumulation, and proteins involved in iron scavenging. In contrast, a much smaller proportion of proteins (37 of 150) that were considered specific to O104:H4 or presented at higher relative abundances in O104:H4 medium had signals targeting them for secretion. These proteins included Shiga toxin 2 subunit B and O104:H4 signature proteins, including AAF/1 major fimbrial subunit and serine protease autotransporters. Most of the abundant proteins from the growth medium of E. coli O104:H4 were annotated as having functions in the cytoplasm. We provide evidence that the extensive presence of cytoplasmic proteins in E. coli O104:H4 growth medium was due to biological processes independent of cell lysis, indicating alternative mechanisms for this potent pathogen releasing cytoplasmic contents into the growth milieu, which could play a role in interaction with the environmental matrices, such as pathogenesis and biofilm formation. IMPORTANCEIn this study, we compared the extracellular proteins from two of the most prominent foodborne pathogenic E. coli organisms that have caused severe outbreaks in the United States and in Europe. E. coli O157:H7 is a well-studied Shiga toxigenic foodborne pathogen of the enterohemorrhagic pathotype that has caused numerous outbreaks associated with various contaminated foods worldwide. E. coli O104:H4 is a newly emerged Shiga toxigenic foodborne pathogen of the enteroaggregative pathotype that gained notoriety for causing one of the most deadly foodborne outbreaks in Europe in 2011. Comparison of proteins in the growth medium revealed significant differences in the compositions of the extracellular proteins for these two pathogens. These differences may provide valuable information regarding the cellular responses of these pathogens to their environment, including cell survival and pathogenesis. E scherichia coli is a diverse species of bacteria including several pathotypes that cause a variety of diseases in humans. Enterohemorrhagic E. coli (EHEC) is responsible for numerous outbreaks of human enterohemorrhagic disease caused by consumption of contaminated food, including meat and fresh vegetables. The primary reservoirs of the most extensively studied EHEC serotype O157:H7 are cattle and other ruminants (1, 2), but E. coli O157:H7 also is capable of long-term survival in various ...

show abstract

Shiga toxin–binding site for host cell receptor GPP130 reveals unexpected divergence in toxin-trafficking mechanisms

Cited by 37 publications

References 31 publications

A Conserved Structural Motif Mediates Retrograde Trafficking of Shiga Toxin Types 1 and 2

A Conserved Structural Motif Mediates Retrograde Trafficking of Shiga Toxin Types 1 and 2

Zinc protects against shiga-toxigenic Escherichia coli by acting on host tissues as well as on bacteria

Different Cellular Origins and Functions of Extracellular Proteins from Escherichia coli O157:H7 and O104:H4 as Determined by Comparative Proteomic Analysis

Contact Info

Product

Resources

About