Effect of SFK inhibitor and Lyn knockout on platelet spreading on immobilized fibrinogen. Microtiter chamber slides were coated with 30 μg/mL of fibrinogen. Washed wild-type mouse platelets were preincubated with DMSO or PP2 (10 μM) for 5 minutes. Wild-type or Lyn^−/− platelets were allowed to adhere and spread on fibrinogen for 90 minutes. Shown in the figure are representative pictures from one of 3 experiments with similar results. The bars in the graph represent the average surface area (± SD) of individual platelets. ***P < .001, compared with DMSO-treated WT platelets. The number of platelets analyzed for each group is indicated above the bars.