CagA, an effector injected into host cells by the type IV secretion system (T4SS) apparatus of Helicobacter pylori, is an oncogenic toxin. Tyrosine phosphorylation at multiple Glu-Pro-Ile-Tyr-Ala (EPIYA) motifs creates a scaffold that interacts with multiple host signaling systems and sometimes allows neoplasias to begin in gastric epithelial cells.
Jiyao W et al.(2023). "The conserved domain database in 2023.",