Fig. 8. The regulatory effect of collagen-IV and laminin-1 on ER levels is mediated by 2, 6 and ß1 integrin subunits. ER protein levels were determined by western blot in primary mammary epithelial cells (A) and in Scp2 cells (B) after 3 days adding mouse IgG (control, c), or 10 µg/ml of 1, 2 or 6 or 5 µg/ml of ß1 integrin blocking antibodies to cells grown on plastic or in the presence of collagen-IV, laminin-1 or rBM. n=3; *P<0.05 versus control (IgG addition).