Figure 2.

Loss of α3 integrin enhances formation of stress fibers and focal contacts. Wild-type (A, C, E, G, I, and K) and α3-deficient (B, D, F, H, J, and L) keratinocytes were grown under normal culture conditions and examined for F-actin (A and B); by interference reflection microscopy for focal contacts (C and D) and by immunofluorescence for vinculin (E and F), talin (G and H), α-actinin (I and J) and phosphotyrosine (K and L). Staining of F-actin with phalloidin showed larger stress fibers in the α3-null keratinocytes (B) than in the wild-type (A) cells (basal-most confocal images). Interference reflection microscopy shows darker and larger focal contacts in the α3-null cells (D) than in the wild-type cells (C). The levels of vinculin, talin, α-actinin, and phosphotyrosine were all increased in the focal contacts of the α3-null keratinocytes (F, H, J, and L) when compared with the wild-type cells (E, G, I, and K). Bars, 10 μm.