Integrin alpha-4/beta-7 (Peyer patches-specific homing receptor LPAM-1) is an adhesion molecule that mediates lymphocyte migration and homing to gut-associated lymphoid tissue (GALT). Integrin alpha-4/beta-7 interacts with the cell surface adhesion molecules MADCAM1 which is normally expressed by the vascular endothelium of the gastrointestinal tract. Interacts also with VCAM1 and fibronectin, an extracellular matrix component. It recognizes one or more domains within the alternatively spliced CS-1 region of fibronectin. Interactions involves the tripeptide L-D-T in MADCAM1, and L-D-V in fibronectin. Binds to HIV-1 gp120, thereby allowing the virus to enter GALT, which is thought to be the major trigger of AIDS disease. Interaction would involve a tripeptide L-D-I in HIV-1 gp120. Integrin alpha-E/beta-7 (HML-1) is a receptor for E-cadherin.
Expressed in a variety of leukocyte lines.
Belongs to the integrin beta chain family. Contains 1 VWFA domain.
Domain I contains three cation-binding sites: the ligand-integrin-binding site (LIMBS), the metal ion-dependent adhesion site (MIDAS), and the adjacent to MIDAS site (ADMIDAS). In the absence of a ligand or in calcium-dependent binding, only ADMIDAS is occupied. In magnesium-dependent binding all three sites bind metal ions. LIMBS positively modify ligand binding whereas ADMIDAS negatively modify ligand binding.