Cofilin association with F-actin during platelet shape change. (A, left, top) Representative gel and immunoblot of actin and cofilin, respectively. Total indicates whole platelets; F-actin, F-actin fraction of the same number of platelets. (Left, bottom) Immunoblot of cofilin associated with F-actin during thrombin-induced shape change. Effect of Y-27632. (Right) Graphic representation of the results. Values are the mean + SD for 4 independent experiments. *Statistically significant; P < .05 with respect to time (0 seconds) in nontreated samples. (B) Bar diagram showing the ratio of cofilin associated with F-actin to F-actin in nontreated platelets (□) and platelets treated with Y-27632 (▪) during thrombin-induced shape change. Values are the mean + SD for 4 independent experiments.