Fig. 2.

Effect of SOCS3 deletion on caveola abundance in endothelial cells. a Upper: Detergent-soluble whole-cell lysates from WT and SOCS3-null AS-M.5 human angiosarcoma-derived ECs treated with either vehicle or 50 μM Fsk for 5 h were equalised for protein content for SDS-PAGE for immunoblotting with the indicated antibodies. Lower: Quantitation of cavin-1 and caveolin-1 protein levels in unstimulated AS-M.5 cells is presented as mean ± standard error for N = 3 experiments. *P < 0.05, **P < 0.01 vs. WT cells. b Transmitting electron microscopy (TEM) was performed on WT and SOCS3-null AS-M.5 cells as indicated. Cell surface caveolae (indicated by the arrows) were readily detectable in WT cells (left panel). In contrast, plasma membranes from SOCS3-null cells were flat and caveolae density was significantly reduced compared to WT cells (right panel). Scale bar = 0.5 μm. c Quantitation of caveola density (number of caveolae per μm of plasma membrane) in WT and SOCS3-null AS-M.5 cells. ***P < 0.0001 vs. WT cells