Cag pathogenicity island protein, CagZ (IPR015139)

Short name: CagPAI_CagZ

Overlapping homologous superfamilies

Family relationships



Helicobacter pylori (Campylobacter pylori) clinical isolates can be classified into two types according to their degree of pathogenicity. Type I strains are associated with a severe disease pathology, express functional VacA (vacuolating cytotoxin A) and contain an insertion of 40 kb of foreign DNA: the cag (cytotoxin-associated gene) pathogenicity island (cagPAI). Type II strains lack the 40 kb insert, cagPAI. The cagPAI may be divided into two regions, cag I and cag II and contain approximately 16 and 15 genes, respectively. The cagPAI encodes a type IV secretion system (T4SS), which delivers CagA into the cytosol of gastric epithelial cells through a rigid needle structure covered by Cag7 or CagY, a VirB10-homologous protein, and CagT, a VirB7-homologous protein, at the base [PMID: 17172510]. The CagA protein is the virulence factor that induces morphological changes in host cells, which may be associated with the development of peptic ulcer and gastric carcinoma [PMID: 16933206].

CagZ is a 23 kDa protein consisting of a single compact L-shaped domain, composed of seven alpha-helices that run antiparallel to each other and 70% of the residues are in alpha-helix conformation: no beta-sheet is present. CagZ is essential for the translocation of the pathogenic protein CagA into host cells [PMID: 15223328].

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.