Regulation of protein S synthesis by growth factors and thrombin.

A. Conditioned media collected from 90% confluent human vascular smooth muscle cell (HVSMC) cultures maintained in serum-free medium for 48 hours in the presence of either control (lane 1), 5 ng/mL basic fibroblast growth factor (b-FGF) (lane 2), 2 ng/mL transforming growth factor beta-1 (TGF-β)1 (lane 3), 5 ng/mL hepatocyte growth factor (HGF) (lane 4), or 5 ng/mL platelet-derived growth factor-BB (PDGF-BB) (lane 5) were analyzed by Western blotting using an anti-protein S polyclonal antibody. B. Conditioned media were collected from 90% confluent cultures maintained in serum-free medium for 24 hours in the presence of either control (lane 1), α-thrombin at either 0.5 U/mL (lane 2), 1 U/mL (lane 3), or 5 U/mL (lane 4). Conditioned media were analyzed by Western blotting using an anti-protein S polyclonal antibody. Arrows indicate cleaved forms of protein S.