The Dock7 signaling pathway is altered in Nbeal2^−/−platelets. (A) Platelet lysates from control and Nbeal2^−/− mice were resolved by SDS-PAGE, and expression levels of Rac1, Cdc42, cofilin, P-cofilin, Iqgap1, Pdxp, and GAPDH were observed by IB with specific antibodies. (B) Densitometry of the results of the blots shown in panel A using Image Studio. (C-D) Time course of active Cdc42 (GTP-Cdc42) and active Rac1 (GTP-Rac1) in platelets stimulated with 0.5 U/mL thrombin. (E) F-actin levels in resting and thrombin-activated platelets. (F) Relative increase in F-actin levels in thrombin-activated vs resting platelets of control and Nbeal2^−/− mice. (G) Representative images of phalloidin-labelled platelets spreading onto fibrinogen in response to thrombin from control and Nbeal2^−/− mice at different magnifications. (H) Quantitation of fully spread and round platelets from control and Nbeal2^−/− mice in response to activation with thrombin or adenosine 5′-diphosphate (ADP). Platelets in 5 random fields per condition were counted, with each field having between 80 and 120 platelets; 4 animals per genotype group were used. Bars represent mean ± SEM. MFI, mean fluorescence intensity. *P values < .05; **P values < .005; ***P values < .0005.