Fig. 2.

K02288 inhibits BMP9-ALK1 signalling in HUVECs. a HUVECs were seeded onto BSA- or Dll4-coated plates and treated with the indicated inhibitors and 10 ng/mL BMP9 for 1 h before collecting and analysing by Western blot. b HUVECs on uncoated plates were treated as indicated with 1 ng/mL BMP9 in the presence or absence of 100 ng/mL ALK1-Fc and similarly analysed by Western blot. c HUVECs on uncoated plates were starved in low serum medium (EGM2 without serum) for 6 h after which the medium was replaced with complete EGM2 in the presence or absence of the indicated inhibitors. Samples were analysed by Western blot. d–f Expression levels of BMP-responsive (d), Notch-responsive (e) and tip cell-specific (f) genes were determined in HUVECs seeded onto BSA- or Dll4-coated plates, 4 h after treatment with 1 μM K02288 and 1 ng/mL BMP9 (d) or 10 ng/mL BMP9 (e, f). g HUVECs were transiently transfected with a RBPJ-responsive luciferase construct for 24 h, re-plated onto BSA- or Dll4-coated plates in the presence or absence of K02288 and luciferase activity determined after 24 h