CD49f is the 125 kDa integrin alpha6 chain which associates noncovalently with the integrin beta1 subunit (CD29) and with the integrin beta4 (CD104) chain to form, respectively, the very late antigen-6 (VLA-6) and alpha6beta4 integrin heterodimers. VLA-6 is expressed on thymocytes, T lymphocytes, monocytes, and platelets. CD49f/CD29 expression is upregulated on activated T lymphocytes and memory T cells. VLA-6 serves as the laminin receptor on platelets, monocytes, and T cells. VLA-6-mediated binding to laminin provides a costimulatory signal to T cells for activation and proliferation.