Fig. 2. Cortactin accumulation precedes cytoskeletal remodelling. Cortactin distribution in serum stimulated (A-C) and PDBu-stimulated A7r5 cells during early (D-F) and late (G-I) phase of podosome formation. Clusters of cortactin are found at the stress fibre/focal adhesion microdomain (arrowheads in A and C; A'-C'). These clusters correspond to the initiation sites of podosomes at which cortactin accumulation increases during their formation. Scale bar: (A-I) 20 µm; (A'-C') 1 µm.