Fig. 5. Role of the catalytic and the growth factor domains of UPA in PDGF- or bFGF-stimulated DNA synthesis by vascular SMC. As described in Fig. 1, growth-arrested cells were exposed to PDGF or bFGF in the presence of 40 µg/ml mAb 394OA against the UPA B-chain (catalytic domain; crosshatched bars), 40 µg/ml mAb 3921 against the UPA A-chain (growth factor domain; right-hatched bars), 40 µg/ml mAb 3936 against the UPAR (inhibition UPA binding; left-hatched bars) or vehicle (open bars). Incorporation of BrdU was determined between 24 and 48 hours of stimulation with PDGF or bFGF and expressed as BrdU-labeling index. Results, given as box-and-whisker plots, are obtained from triplicate determinations in six independent experiments. P<0.001 for differences in BrdU-LI between cells treated with mAb 394OA and vehicle under stimulation with either PDGF (A) or bFGF (B).