Cdc42−/− mice display mild thrombocytopenia. (A) Western blot analysis of Cdc42 expression in wild-type and Cdc42−/− platelets. GPIIIa expression was used as loading control. (B) Peripheral platelet counts (n = 6 per group). Error bars: wt, 860.95 ± 176.94; Cdc42−/−, 489.41 ± 128.91 (×103)/μL; ***P < .001. (C) Representative TEM pictures from wild-type and Cdc42−/− platelets. Scale bar equals 2 μm. (D) Cdc42−/− platelets are increased in size. Mean platelet width of wild-type and Cdc42−/− platelets (n = 25 per group). Error bars: wt, 0.64 ± 0.14; Cdc42−/−, 0.85 ± 0.21 [μm]; ***P < .001.