Figure 5

U373-MG cells were cultured on soft (A, C, E) or stiff (B, D, F) polyacrylamide hydrogels and immunofluorescently stained for vinculin (A, B) and phospo-EGFR (C, D). There are no punctate vinculin-positive focal adhesions on soft substrates (A), while there are large focal adhesions on stiff substrates (C). On stiff substrates, there are distinct, punctate pEGFR structures (D; arrows) that colocalize with vinculin positive adhesions (F; arrows). The colocalization is more clearly evident in the high-magnification insets (B, D). Scale bar is 50 microns.