Figure 3. Compound screening procedure. Cells were plated on 96-well plates. A single drug from the library was added to a single well on each of three 96-well plates. The three plates contained (A) cells alone plus compound, to identify agonists, (B) cells alone plus compound plus low-dose transforming growth factor-β (TGFβ; 0.06 ng/mL), to identify synergists, and (C) cells alone plus compound plus high-dose TGFβ (0.5 ng/mL), to stimulate the reporter maximally and identify inhibitors.