ELMO1 regulates integrin-mediated platelet spreading. (A) Representative images of murine platelets incubated on fibrinogen-coated plates for the times indicated and fixed and stained with FITC-phalloidin. The images were obtained using confocal microscope. Scale bars, 5 μM. (B) Quantification of platelets with a filopodial phenotype expressed as a percentage of adhered platelets. At least 3 fields containing at least 25 platelets were analyzed per replicate (at least 2 replicates per experiment). Data were analyzed via Student t test (*P < .05). WT and ELMO1^−/−, n = 4.