Fig. 3. Inhibition of adhesion spikes by rolipram requires the activation of PKA. (A) Cells were transfected with the protein kinase A inhibitor PKI before being plated onto laminin in the presence of rolipram. Cells were fixed 1 hour after plating and stained for PKI (green) and actin (red). (B) Non-transfected cells were plated onto laminin in the presence of 8Br-cAMP or 8CPT-2Me-cAMP (both 300 µM). Cells were fixed 1 hour after plating and stained for Scar1 (green) and actin (red). Scale bars, 40 µm.