Deletion of mTORC1 suppresses MK differentiation and platelet function. (A) Ultrastructure and proplatelet formation of MKs from 12-month-old Raptor KO and WT mice (n = 8). Values represent means ± SEM; **P < .01. (B) Ploidy formation of 12-month-old WT and Raptor KO mice (n = 8). Values represent means ± SEM; *P < .05. (C) FACS analysis of platelets incubated with 0.2 U/mL thrombin for 15 minutes at room temperature from mice described in panel A for platelet integrin αIIbβ3 activation and quantification illustrated (n = 8). Values represent means ± SEM; **P < .01. Adenosine 5′-diphosphate–induced (20 μM) platelet aggregation in PRP (D) and thrombin-induced (0.2 U/mL) platelet spreading analysis (E) from mice described in panel A (n = 8). Values represent means ± SEM; **P < .01; *P < .05. (F) PF4 ELISA analysis of plasma from 12-month-old WT and Raptor KO mice. Values represent means ± SEM; *P < .05. WT and Raptor KO mice were subjected to fibrin formation (G) and clot formation (H) assays (n = 5). Values represent means ± SEM; **P < .01; *P < .05. (I) Tail bleeding time (tBT) analysis of WT and Raptor KO mice (n = 10). Values represent means ± SEM; **P < .01.