Arf6 KO platelets are defective in Fg storage but not in other cargo. (A) Comparison of proteins levels by western blotting between wild-type (WT) and KO platelets. Washed platelet extracts (1 × 107/lane) were loaded, and the indicated proteins were probed for by western blotting using the corresponding antibodies. β-Actin was used as a loading control. The data are representative of at least 3 independent experiments. (B) Comparison of endogenous Fg levels between WT and KO platelets. (i) Washed platelet extracts (1 × 107/lane) were loaded, and the indicated proteins were probed for by western blotting using corresponding antibodies. Each lane represents platelets from a single mouse. RabGDI was used as a loading control. (ii) Quantification of Fg levels in panel Bi was performed using ImageQuantTL and analyzed by SigmaPlot 12.0. (C) Comparison of granule cargo levels between WT and KO platelets. Washed platelet extracts (1 × 107/lane) were loaded, and the indicated proteins were probed for by western blotting using corresponding antibodies. β-Actin was used as a loading control. Quantification was performed using ImageQuantTL, and ratio of KO to WT was calculated. The dash line represents ratio of 1 (KO/WT). The data are representative of at least 2 independent experiments.