Fig. 5. Phalloidin staining of cells expressing WT and mutant profilin I. (A) PC12 cells were plated on poly-D-lysine-coated coverslips and F-actin was stained 60 hours after treatment with 20 ng/ml NGF and 10 µM forskolin. Note that neurite outgrowth on poly-D-lysine is slower than on collagen, resulting in fewer and shorter neurites (compare with Fig. 3A). (B) CAD cells were transiently transfected with IRES-GFP constructs of profilin I WT and mutants. All cells shown are transfected based on the GFP signal (not shown), except for one non-transfected cell in W3A(2), which is indicated with an arrowhead. The arrow in W3A(1) indicates a ridge of densely packed filopodia. Bars, 25 µm (A); 50 µm (B).