FIGURE 6.

PKA activation enlarges membrane protrusions. MDA-MB-231 cells were seeded on coverslips coated with type I collagen. Cells were stimulated by Fsk (10 μm) and IBMX (100 μm) for 30 min with and without preincubation with H-89 (20 μm) for 15 min and then stained with phalloidin. The length of phalloidin-positive protrusions was quantified using ImageJ software. A, cells were classified according to the length of their largest protrusion (n > 250, combination of three independent experiments). White and black bars indicate cells treated with dimethyl sulfoxide (DMSO) and Fsk, respectively. Gray bars indicate H-89-preincubated cells treated with Fsk. B, shown is the average length of protrusions from three independent experiments.