Impact of JAK2, HSP90, PI3K, and MEK signaling inhibitors on CFU-MK. Day 10-CD34+/CD43+ cells were seeded in fibrin clot assay with SCF and with or without TPO in presence of various inhibitors. (A), Ruxolitinib +TPO (mean ± SEM, WT, P38 and P35: n = 3). (B), Ruxolitinib ±TPO (mean ± SEM, P38 and P35: n = 3). (C), AUY922 + TPO (mean ± SEM, WT, P38 and P35: n = 3). (D), AU922 ±TPO (mean ± SEM, P38 and P35: n = 3). (E), LY94002 ±TPO (mean ± SEM, WT, P38 and P35: n = 3). (F), LY94002 ± TPO (mean ± SEM, P38 and P35: n = 3). (G), UO126 +TPO (mean ± SEM, WT, P38 and P35: n = 3). (H), UO126 ±TPO (mean ± SEM, P38 and P35: n = 3). (I, J), IC50 were calculated for each curve. (I), The graph represents the IC50 for WT and CALRdel52 (P35 and P38) in the presence of TPO. (J), The graph represents the IC50 for CALRdel52 (P35 and P38) in the presence or absence of TPO. *P < 0.05. Student t test. CFU-MK = colony forming unit-megakaryocyte; HSP90 = heat shock protein 90; IC50 = half-maximal inhibitory concentration; JAK2 = Janus Kinase 2; MEK = mitogen-activated protein kinase; PI3K = phosphoinositide 3-kinase; SCF = stem cell factor; SEM = standard error of the mean; TPO = thrombopoietin; WT = wild-type.