Hck^−/− BMDMs do not form large podosome rosettes. BMDMs were seeded on fibronectin-coated coverslips for 24 hours, fixed, and permeabilized. F-actin was stained with Texas red–coupled phalloidin; vinculin, with primary and FITC-coupled secondary antibodies; and nuclei, with DAPI, and cells were examined by fluorescence microscopy. (A top 2 panels) Characteristic podosomes are present in wt and Hck^−/− BMDMs with an actin core surrounded by a ring of vinculin (insets). (Bottom 2 panels) wt BMDMs form a large podosome rosette (arrowhead on the Merge image); Hck^−/− BMDMs do not form large, but small, podosome rosettes (arrowhead; scale bar represents 10 μm; magnification ×100). (B) Quantification of podosome rosettes in wt and Hck^−/− BMDMs. Rosettes were counted in at least 100 cells in duplicate (n = 4). (C) Quantification of small and large rosettes in wt and Hck^−/− BMDMs. Hck^−/− BMDMs preferentially form small podosome rosettes (n = 4); **P < .01; ***P < .001.