Functional regulation of the human integrin VLA‐1 (CD49a/CD29) by divalent cations and stimulatory β1 antibodies

Abstract

We have investigated the regulation by divalent cations Mg2+, Ca2+ and Mn2+ of the functional activity of the human integrin VLA-1 expressed on neuroblastoma NB100 cells. VLA-1-mediated adhesion of NB100 cells to ligand collagen type I was supported by either mM concentrations of extracellular Mg2+ or μM levels of Mn2+. In contrast, Ca2+ alone did not induce activation of VLA-1 but exerted a potent inhibitory effect on the Mg2+-supported cell adhesion. We have also demonstrated that VLA-1 can be directly activated by the stimulatory monoclonal antibody TS2/16 specific for the integrin β1 subunit, resulting in effective adhesion of NB100 cells to type I collagen. This study has been possible by using a novel blocking VLA-α1 specific monoclonal antibody, 5E8D9