Figure 5.

Arhgef1 deletion impairs clot retraction and platelet spreading. A, Whole blood was collected from both Arhgef1^−/− and wild‐type (WT) mice and washed platelets were isolated as discussed in the Methods section. Clot retraction was initiated by adding thrombin (0.1 U/mL) and photographed every 5 minutes for 30 minutes. B, Arhgef1^−/− and WT platelets were allowed to adhere to fibrinogen‐coated coverslips for 5 minutes after stimulation with thrombin (0.1 U/mL). Tetramethylrhodamine‐conjugated phalloidin in 10% fetal bovine serum/PBS with 0.2% saponin was used to stain for F‐actin and imaged using Leica DMi8 inverted widefield fluorescence microscope with integrated high precision focus drive. Images were processed using LAS X Wizard imaging software. Data are representative of 3 independent experiments. Each experiment was repeated at least 3 times, with blood pooled from a group of 8 mice each time.