Platelet activation by ionomycin is unaffected in the absence of CypD. Platelets isolated from CypD^+/+ (□) or CypD^−/− (■) mice were left unstimulated (Unstim) or stimulated with ionomycin (Ion) (3 μM) for 5 minutes. Percentages of (A) annexin V^high and (B) fibrinogen^high platelets are shown (n = 4). #P < .05 compared with unstimulated CypD^+/+ platelets. Error bars represent SE.