Cryo-EM Analysis Reveals Structural Basis of Helicobacter pylori VacA Toxin Oligomerization

Su, Min; Erwin, Amanda L.; Campbell, Anne M.; Pyburn, Tasia M.; Salay, Lauren E.; Hanks, Jessica L.; Lacy, D. Borden; Akey, D.L.; Cover, Timothy L.; Ohi, Melanie D.

doi:10.1016/j.jmb.2019.03.029

Cited by 20 publications

(17 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The relevance of these toxin components lays in the fact that s1 causes vacuolation of mammalian cells whereas s2 do not [37]; the discrepancy may be attributed to differences in channel-forming properties [38]. The combination of different VacA alleles is associated with more virulent strains and severe gastric disease: s1a/m2 strains are found in 87.5% of patients with peptic ulcer and in 93% of patients with gastric carcinoma [39]; other highly pathogenic associations include s1a/m1b, s1b/m1b, and s2/m2 [33]. VacA is involved in bacterial colonization of epithelial cells of the gastric mucosa via formation of low conductance membrane pores that are selective for anions over cations [40], and the induction of vacuole formation [41].…”

Section: Vacamentioning

confidence: 99%

Effect of Helicobacter pylori on Tight Junctions in Gastric Epithelia

Rendón-Huerta¹,

García-García²,

Estrada³

2021

Helicobacter Pylori - From First Isolation to 2021

View full text Add to dashboard Cite

Molecular complexes grouped under the names of tight, adherent or gap junction regulate the flow of water, ions and macromolecules through epithelium paracellular spaces. The main constituents of tight junctions are claudins, a family of 26 different proteins whose expression and distribution are tissue specific but varies in tumors. A change in claudin 1, 3, 4, 5, 6, 7, 9 and 18 expression, that contributes to lose epithelial cohesion, has been associated to enhanced cell proliferation, migration, and invasiveness in gastric neoplastic tissue. Chronic inflammation process induced by H. pylori infection, a major risk factor for gastric cancer development, disrupts tight junctions via CagA gene, Cag pathogenicity island, and VacA, but the effect upon the epithelial barrier of H. pylori lipopolysaccharides or H. pylori-induced up-regulation of mTOR and ERK signaling pathways by microRNA-100 establishes new concepts of proof.

show abstract

Section: Vacamentioning

confidence: 99%

Effect of Helicobacter pylori on Tight Junctions in Gastric Epithelia

Rendón-Huerta¹,

García-García²,

Estrada³

2021

Helicobacter Pylori - From First Isolation to 2021

View full text Add to dashboard Cite

show abstract

“…1). Figure 1B shows the cryoelectron microscopy (cryo-EM) structure of a hexamer formed by wild-type VacA from strain 60190 and depicts regions that were replaced with VacA sequences from strain Tx30a (29,30). Each of these chimeric VacA proteins was secreted into the extracellular space, and the secreted proteins were successfully purified by use of Strep-tag II.…”

Section: Replacement Of M1mentioning

confidence: 99%

“…The secreted 88-kDa VacA protein is comprised of an N-terminal p33 domain and a C-terminal p55 domain (25,26). Crystallographic and electron microscopic studies indicate that both domains have predominantly ␤-helical structure (27)(28)(29)(30). Both the p55 and p33 domains contribute to the process by which VacA binds to host cells (26).…”

mentioning

confidence: 99%

Functional Properties of Helicobacter pylori VacA Toxin m1 and m2 Variants

et al. 2020

Self Cite

View full text Add to dashboard Cite

Helicobacter pylori colonizes the gastric mucosa and secretes a pore-forming toxin (VacA). Two main types of VacA, m1 and m2, can be distinguished by phylogenetic analysis. Type m1 forms of VacA have been extensively studied, but there has been relatively little study of m2 forms. In this study, we generated H. pylori strains producing chimeric proteins in which VacA m1 segments of a parental strain were replaced by corresponding m2 sequences. In comparison to the parental m1 VacA protein, a chimeric protein (designated m2/m1) containing m2 sequences in the N-terminal portion of the m region was less potent in causing vacuolation of HeLa cells, AGS gastric cells, and AZ-521 duodenal cells and had reduced capacity to cause membrane depolarization or death of AZ-521 cells. Consistent with the observed differences in activity, the chimeric m2/m1 VacA protein bound to cells at reduced levels compared to the binding levels of the parental m1 protein. The presence of two strain-specific insertions or deletions within or adjacent to the m region did not influence toxin activity. Experiments with human gastric organoids grown as monolayers indicated that m1 and m2/m1 forms of VacA had similar cell-vacuolating activities. Interestingly, both forms of VacA bound preferentially to the basolateral surface of organoid monolayers and caused increased cell vacuolation when interacting with the basolateral surface compared to the apical surface. These data provide insights into functional correlates of sequence variation in the VacA midregion (m region).

show abstract

“…Recently, cryo-EM studies have reported that there is a missing region at residues 300–334 between p33 and p55 domains (HP strain 60,190), which manifests as a weak and discontinuous density in the center of all vacA oligomers on a 3D map. The authors suggest that this region represents a highly flexible loop found between the p33 and p55 domains [ 20 , 21 ]. Therefore, we also performed predictions about the secondary structure and physicochemical properties of this particular region.…”

Section: Introductionmentioning

confidence: 99%

New genotypes of Helicobacter Pylori VacA d-region identified from global strains

Soyfoo

Doomah

et al. 2021

BMC Mol and Cell Biol

View full text Add to dashboard Cite

Background Pathogenesis of Helicobacter Pylori (HP) vacuolating toxin A (vacA) depends on polymorphic diversity within the signal (s), middle (m), intermediate (i), deletion (d) and c-regions. These regions show distinct allelic diversity. The s-region, m-region and the c-region (a 15 bp deletion at the 3′-end region of the p55 domain of the vacA gene) exist as 2 types (s1, s2, m1, m2, c1 and c2), while the i–region has 3 allelic types (i1, i2 and i3). The locus of d-region of the vacA gene has also been classified into 2 genotypes, namely d1 and d2. We investigated the “d-region”/“loop region” through bioinformatics, to predict its properties and relation to disease. One thousand two hundred fifty-nine strains from the NCBI nucleotide database and the dryad database with complete vacA sequences were included in the study. The sequences were aligned using BioEdit and analyzed using Lasergene and BLAST. The secondary structure and physicochemical properties of the region were predicted using PredictProtein. Results We identified 31 highly polymorphic genotypes in the “d-region”, with a mean length of 34 amino acids (9 ~ 55 amino acids). We further classified the 31 genotypes into 3 main types, namely K-type (strains starting with the KDKP motif in the “d-region”), Q-type (strains starting with the KNQT motif), and E-type (strains starting with the ESKT motif) respectively. The most common type, K-type, is more prevalent in cancer patients (80.87%) and is associated with the s1i1m1c1 genotypes (P < .01). Incidentally, a new region expressing sequence diversity (2 aa deletion) at the C-terminus of the p55 domain of vacA was identified during bioinformatics analysis. Conclusions Prediction of secondary structures shows that the “d-region” adopts a loop conformation and is a disordered region.

show abstract

Cryo-EM Analysis Reveals Structural Basis of Helicobacter pylori VacA Toxin Oligomerization

Cited by 20 publications

References 60 publications

Effect of Helicobacter pylori on Tight Junctions in Gastric Epithelia

Effect of Helicobacter pylori on Tight Junctions in Gastric Epithelia

Functional Properties of Helicobacter pylori VacA Toxin m1 and m2 Variants

New genotypes of Helicobacter Pylori VacA d-region identified from global strains

Contact Info

Product

Resources

About