Figure 4. PAK4 inhibition sensitizes HUVECs to TNF-induced EMP release. (A) Western blotting of HUVECs transfected 48 h with PAK4 or control siRNAs, or treated 24 h with PAK4 inhibitor PF-3758309, and analyzed by PAK4 and control tubulin antibodies. (B) Immunofluorescence of HUVECs transfected with PAK4 or control siRNAs, or treated with PF-3758309, and stained by anti-PAK4 antibody; scale bar = 10 μm. (C) EMP release measured by FC in HUVECs transfected 48 h with PAK4 or control siRNAs, or treated 24 h with PF-3758309, and stimulated 24 h with TNF (100 ng/ml). (D) Time course of EMP release in TNF-treated HUVECs transfected 48 h with PAK4 or control siRNAs, or incubated 24 h with PF-3758309; * P<0.05, ** P<0.01.