Topological analysis of a putative virB8 homologue essential for the cag type IV secretion system in Helicobacter pylori

Buhrdorf, Renate; Forster, Cornelia; Haas, Rainer; Fischer, Wolfgang

doi:10.1078/1438-4221-00260

Cited by 36 publications

(28 citation statements)

References 18 publications

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“…In NTF2-like molecules exhibiting this pocket, it is either used for protein-protein interactions, as is the case for NTF2 (32) and CamKII (31), or forms the active site of a large class of lipid and steroid enzymes (33). This important feature of VirB8 could (38). Strictly conserved, strongly conserved, and conserved residues are marked in red, magenta, and light pink, respectively.…”

Section: Resultsmentioning

confidence: 99%

Structures of two core subunits of the bacterial type IV secretion system, VirB8 from Brucella suis and ComB10 from Helicobacter pylori

Terradot

Bayliss

Oomen

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

113

154

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Type IV secretion systems (T4SSs) are commonly used secretion machineries in Gram-negative bacteria. They are used in the infection of human, animal, or plant cells and the propagation of antibiotic resistance. The T4SS apparatus spans both membranes of the bacterium and generally is composed of 12 proteins, named VirB1-11 and VirD4 after proteins of the canonical Agrobacterium tumefaciens T4SS. The periplasmic core complex of VirB8͞VirB10 structurally and functionally links the cytoplasmic NTPases of the system with its outer membrane and pilus components. Here we present crystal structures of VirB8 of Brucella suis, the causative agent of brucellosis, and ComB10, a VirB10 homolog of Helicobacter pylori, the causative agent of gastric ulcers. The structures of VirB8 and ComB10 resemble known folds, albeit with novel secondary-structure modifications unique to and conserved within their respective families. Both proteins crystallized as dimers, providing detailed predictions about their self associations. These structures make a substantial contribution to the repertoire of T4SS component structures and will serve as springboards for future functional and protein-protein interaction studies by using knowledge-based site-directed and deletion mutagenesis.protein͞DNA transport ͉ Gram-negative bacteria ͉ structural biology ͉ crystallography

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Section: Resultsmentioning

confidence: 99%

Structures of two core subunits of the bacterial type IV secretion system, VirB8 from Brucella suis and ComB10 from Helicobacter pylori

Terradot

Bayliss

Oomen

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

113

154

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“…Since this interaction has also been found in a yeast two-hybrid assay (S. Kutter and W. Fischer, unpublished data), and can be demonstrated in E. coli by immunoprecipitation (Couturier et al, 2006), it is a very strong and direct interaction. To test whether the interaction in H. pylori depends on the presence of other cag-encoded factors, notably the coupling protein homologue Cagb, we performed immunoprecipitation experiments on the cagV (hp530) mutant of strain 26695, with CagV representing an essential secretion apparatus component, and on the cagI (hp540), cagZ (hp526) and cagb (hp524) mutants, which lack genes encoding further CagA translocation factors (Fischer et al, 2001b;Buhrdorf et al, 2003). However, the amount of CagF coprecipitating with CagA was unchanged in these mutants (Fig.…”

Section: Cagf Interacts With Caga Independently Of Other Translocatiomentioning

confidence: 99%

The Helicobacter pylori CagF protein is a type IV secretion chaperone-like molecule that binds close to the C-terminal secretion signal of the CagA effector protein

Pattis¹,

Weiss²,

Laugks³

et al. 2007

Microbiology

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“…Most known T4SSs in bacterial pathogens are encoded by genes showing ancestral relation to the genes encoding the VirB/D4 apparatus in A. tumefaciens. Helicobacter pylori possesses orthologs to all the VirB/D4 transport system proteins except VirB6 and the pilus subunits VirB2 and VirB5 (2,10,13,29). Furthermore, the eight known VirB/D4 orthologs in H. pylori are absolutely required for translocation of CagA, along with 10 additional Cag proteins for which there is no detectable sequence similarity in the database (20).…”

mentioning

confidence: 99%

Interaction with CagF Is Required for Translocation of CagA into the Host via theHelicobacter pyloriType IV Secretion System

et al. 2006

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Development of severe gastric diseases is strongly associated with those strains of Helicobacter pylori that contain the cag pathogenicity island (PAI) inserted into the chromosome. The cag PAI encodes a type IV secretion system that translocates the major disease-associated virulence protein, CagA, into the host epithelial cell. CagA then affects host signaling pathways, leading to cell elongations and inflammation. Since the precise mechanism by which the CagA toxin is translocated by the type IV secretion system remained elusive, we used fusion proteins and immunoprecipitation studies to identify CagA-interacting secretion components. Here we demonstrate that CagA, in addition to other yet-unidentified proteins, interacts with CagF, presumably at the inner bacterial membrane. This interaction is required for CagA translocation, since an isogenic nonpolar cagF mutant was translocation deficient. Our results suggest that CagF may be a protein with unique chaperone-like function that is involved in the early steps of CagA recognition and delivery into the type IV secretion channel.

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Topological analysis of a putative virB8 homologue essential for the cag type IV secretion system in Helicobacter pylori

Cited by 36 publications

References 18 publications

Structures of two core subunits of the bacterial type IV secretion system, VirB8 from Brucella suis and ComB10 from Helicobacter pylori

Structures of two core subunits of the bacterial type IV secretion system, VirB8 from Brucella suis and ComB10 from Helicobacter pylori

The Helicobacter pylori CagF protein is a type IV secretion chaperone-like molecule that binds close to the C-terminal secretion signal of the CagA effector protein

Interaction with CagF Is Required for Translocation of CagA into the Host via theHelicobacter pyloriType IV Secretion System

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