DC podosomes degrade extracellular matrix. (A) SDC were plated onto thin layers of cross-linked FITC-gelatin for 4 h and fixed, then podosomes were stained with TRITC-phalloidin. (B) xz and yz sections through a z series of confocal images revealed precise coincidence between individual podosomes and holes in the matrix (arrows). (C) BMDC infected with a GFP-actin–expressing retrovirus were plated onto Alexa 594–gelatin, and confocal images were collected every 2 min over a 220-min period. Images from individual time points of Video 2 are shown. (D) SDC were treated with 50 ng/ml LPS for 10, 60, or 120 min before plating on FITC-gelatin for a further 2 h. Bars: (A and C) 10 μm; (B) 5 μm; (D) 20 μm.