FIGURE 3.

Mn²⁺ prevents EGF inhibition of α5β1 integrin function in A431 (A) and DiFi (B) cells. Cells were pretreated for 1 h at room temperature with solvent control, 0.5 mm MnCl₂, control mouse IgG (20 μg/ml), or anti-β1 integrin blocking antibody P5D2 (20 μg/ml). Cells were then seeded onto fibronectin-coated wells in the presence of EGF (10 nm) for 60 min (A431 cells) or 75 min (DiFi cells) at 37 °C. Cell adhesion was assessed as described in the legend to Fig. 1. Additions to the medium were as indicated. Error bars indicate S.D. of triplicate samples for one of three representative experiments.