Figure 4. H. pylori type IV secreted effector proteins Cag Y, L, I and A form an association with the type IV secretion system (T4SS) and bind to the β₁ chain of integrins.

Injection of Cag A via the T4SS requires a conformational change in the β₁ chain in addition to integrin clustering. An antibody that locks the conformation of β₁ integrin was able to prevent CagA delivery. It is concluded therefore that the physical change of the integrin upon binding is needed for insertion of the T4SS tip and subsequent injection of effector proteins.