Fig. 8. Proteolytic activity associated with HUVEC podosomes. (A) ECM degradation is associated with v-Src- and PMA-induced podosomes. HUVECs were seeded on FITC-gelatin-coated coverslips. The cells were either transfected with v-Src-encoding or V12Cdc42-encoding plasmids or treated with PMA for 1 hour. Cells were fixed and stained for F-actin. Areas of degraded gelatin that overlap (arrows) or not (filled arrowheads) with podosomes are shown. Podosomes that do not colocalise with matrix degradation areas are also shown (opened arrowheads). Cell contours have been digitally rendered in the micrographs. (B) ECM degradation is inhibited by MMP inhibitors. The experiment described in A for PMA-treated cells was in the presence of 10 µM of GM6001 or 10 µM TSRI265. `Black holes' representative of gelatin degradation were quantified and are presented as percentage of the control response obtained with untreated cells. Error bars represent the mean ± s.d. of three independent experiments.