Fig. 4. Gelsolin effects on the actin cytoskeleton in clusters of pancreatic acinar cells. (A) Permeabilized cells were treated for 5 minutes with a BRB80 solution containing 1.3 µM recombinant gelsolin either in the presence of EGTA (left) or in the presence of 1 mM Ca²⁺ (right). Cells were then fixed in paraformaldehyde and stained with phalloidin. We observed gelsolin effects on the F-actin network only in the presence of Ca²⁺, with a reduction in apical F-actin (arrows) and a substantial loss in the basal pole (arrowheads). Bars, 10 µm.