This family consists of bacterial and viral proteins which are very similar to the Zonular occludens toxin (Zot). Zot is elaborated by bacteriophages present in toxigenic strains of Vibrio cholerae. Zot is a single polypeptide chain of 44.8 kDa, with the ability to reversibly alter intestinal epithelial tight junctions, allowing the passage of macromolecules through mucosal barriers [1,2]

1: Zonula occludens toxin (Zot) interferes with the induction of nasal tolerance to gliadin. Rossi M, Maurano F, Luongo D, Fasano A, Uzzau S, Auricchio S, Troncone R; Immunol Lett 2002;81:217-221. PMID:11947928

2: Zonula occludens toxin increases the permeability of molecular weight markers and chemotherapeutic agents across the bovine brain microvessel endothelial cells. Karyekar CS, Fasano A, Raje S, Lu R, Dowling TC, Eddington ND; J Pharm Sci 2003;92:414-423. PMID:12532391