Myr-Arf6 peptide blocks the activation of Rho family GTPases. Washed platelets (4 × 10⁸/mL) were incubated with DMSO or indicated Arf peptides (25 μM) for 2 minutes with stirring at 37°C, followed by stimulation with 0.1 μg/mL convulxin for the indicated times (A-B). The platelet suspensions were lysed and the supernatants were used to pull down the indicated small GTPases, as described in “Materials and methods.” Western blots were performed using anti-Arf6, anti-Rap1, anti-RalA, anti-Rac1, anti-Cdc42, and anti-RhoA antibodies.