Vacuolating cytotoxin A p55 domain (VacA p55)

Vacuolating cytotoxin A (VacA) is a potent protein toxin secreted by Helicobacter pylori, a bacterium strongly linked to the development of peptic ulcers and gastric adenocarcinoma (UniProt P55981). The mature 88 kDa toxin is composed of two main domains: the N-terminal p33 domain and the C-terminal p55 domain (PubMed: 10490605). The p55 domain is essential for the toxin's ability to bind to the surface of host gastric epithelial cells, interacting with various receptors such as receptor-like protein tyrosine phosphatase beta (RPTPβ) and sphingomyelin (PubMed: 15941011). Following binding and internalization, VacA forms anion-selective channels in endosomal and mitochondrial membranes, leading to massive vacuolation, mitochondrial damage, and programmed cell death (PubMed: 22491015). Furthermore, VacA exerts immunomodulatory effects by inhibiting T-cell proliferation and activation, which facilitates chronic bacterial persistence (PubMed: 11274168). Given its critical role in H. pylori virulence, the p55 domain is a primary target for therapeutic interventions, including neutralizing antibodies and small-molecule inhibitors designed to block toxin attachment and subsequent cellular damage (PubMed: 25605869).

Other names

p55 subunitVacA p55Vacuolating cytotoxin p55VacA binding domain

Inhibition of toxin binding to host cell receptors and prevention of toxin oligomerization.