CD49d (integrin alpha 4), also known as very late antigen 4 alpha (VLA-4 alpha) is a cell surface glycoprotein constituting integrin complexes. CD49d heterodimerizes with CD29 (integrin beta 1) to form VLA-4 antigen, which is involved in cell-cell and cell-extracellular matrix interactions, which is a receptor for CD106 (VCAM) and fibronectin. CD79d also heterodimerizes with integrin beta 7 to form LPAM-1, which binds to MAdCAM-1 (mucosal vascular addressin) . These interactions are important for cell adhesion and activation.