An alpha 1/beta 1-like integrin receptor on rat aortic smooth muscle cells mediates adhesion to laminin and collagen types I and IV.

Extracellular matrix receptors on vascular smooth muscle cells may enable the cells to migrate through both interstitial and basement membrane matrices during vascular remodelling after injury. Rat aortic smooth muscle cells attach to surfaces coated with fibronectin, laminin, and collagen types I and IV. Members of the beta 1 family of integrin receptors appear to mediate attachment to these extracellular matrix components. We used a monoclonal antibody, 3A3, to identify a 185/120 kD, alpha 1/beta 1-like, heterodimeric integrin receptor that mediates rat aortic smooth muscle cell adhesion to collagen types I and IV as well as to laminin. This receptor appears to be the only beta 1 integrin receptor mediating adhesion to type IV collagen. On the other hand, the smooth muscle cells have several other beta 1 integrin receptors in addition to the 185/120 kD receptor that bind to laminin- and to collagen type I-Sepharose affinity columns. By using 3A3 to inhibit only the 185/120 kD receptor, we suggest that these other receptors also can be used by rat aortic smooth muscle cells to attach to laminin and collagen type I.