Barbell-shaped proplatelet enrichment in PI3K-C2α^WT/D1268A mice. (A) Washed platelets were immediately fixed (baseline) or cultured in suspension for 24 hours (cultured). Panels display a representative example where the platelets were stained for α-tubulin. Scale bar: 5 μm. The bar graph indicates the number of platelets with at least 2 cell bodies per microliter (mean ± SEM; n = 4; ***P < .001 vs WT according to 2-tailed Student t test). (B) Washed platelets were perfused on murine vWF-coated microcapillaries at 18 dynes/cm². 2 cell bodies platelets and discoid platelets were visualized by real-time videomicroscopy. The percentage of 2 cell bodies platelets on total platelets was calculated (mean ± SEM; n = 3; *P < .05 and **P < .01 vs WT according to 2-tailed Student t test). Schematic representation of dynamic platelet release from preplatelets through barbell-shaped proplatelets. (C) Washed platelets from WT mice transplanted with WT bone marrow (WT > WT), PI3K-C2α^WT/D1268A mice transplanted with WT bone marrow (WT > WT/D1268A), WT mice transplanted with PI3K-C2α^WT/D1268A bone marrow (WT/D1268A > WT), and PI3K-C2α^WT/D1268A mice transplanted with PI3K-C2α^WT/D1268A bone marrow (WT/D1268A > WT/D1268A) mice were treated as described in A (mean ± SEM; n = 3; *P < .05, **P < .01, and ***P < .001, according to 2-way ANOVA).