Fig. 1. The cytoplasmic protein ß₃-endonexin downregulates uPAR protein expression in endothelial cells. (A) Immunoblot of endogenous ß₃-endonexin. Lysates of platelets, HUVECs and human placenta tissue were evaluated by immunoblotting with the help of a specific polyclonal anti-ß₃-endonexin antiserum. A purified recombinant His-tagged ß₃-endonexin (14 kDa) served as antigen control. (B) FACS. Confluent monolayers of endothelial cells were transiently transfected with GFP/En-S, GFP/En-L, or GFP control vector. After 48 hours cells were stained with anti-uPAR mAb and evaluated by flow cytometry. The mean intensity±s.e.m. of uPAR immunofluorescence of GFP-positive cells in four experiments was used as an index of uPAR protein expression.