DGKζ-KO platelets exhibit enhanced platelet spreading on substrates for both GPVI and integrin αIIbβ3. Washed platelets from WT and DGKζ-KO mice were allowed to adhere on immobilized CRP (50 μg/mL), collagen (50 μg/mL), or fibrinogen (30 μg/mL) for the indicated times at 37°C. After washing with phosphate-buffered saline to remove unbound platelets, adherent platelets were fixed and stained with phalloidin-TRITC. (A) Images of spread platelets representative of 3 independent experiments are shown. Bars represent 10 μm. (B) The average area covered by individual platelets was quantified from at least 4 images per substrate and 250 to 500 platelets per time point. Spreading area is reported as the mean ± SEM. Statistical analysis was performed using the unpaired Student t test. ****P < .0001 of DGKζ-KO as compared with WT.