Fig. 4. Organization of actin filaments, paxillin and phosphotyrosine following the binding of polyacrylamide beads. Actin (a), phosphotyrosine (c), and paxillin (e) are concentrated beneath bound stiff beads (arrows). However, only phosphotyrosine (d) and paxillin (f), but not actin (b), are concentrated beneath bound soft beads (b,d,f; arrows). Beads are represented as gray circles in panels a and b. Owing to the high intensity of actin staining, weak fluorescence of these beads is not detectable in these prints. Bar, 6 µm.