Twf2a^−/− platelets are less prone to apoptosis. Platelet apoptosis was assessed using Anxa5-FITC binding to exposed phosphatidylserine (A) or the mitochondrial membrane potential sensor 3,3′-dihexyloxacarbocyanine iodide (DiOC₆(3); B-C). A23187, Ca²⁺ ionophore; CRP, collagen-related peptide; rest, resting; Rhd, rhodocytin; U46, U46619, a stable thromboxane A₂ analog. Values are mean ± SD (n = 6). ***P < .001, **P < .01, and *P < .05, unpaired Student t test.