Figure 4. Inhibitory effect of R667 on the TGF-β1-induced phosphorylation of FAK in HTFs cultured in collagen gels. A: Cells embedded in collagen gels were incubated first for 12 h with various concentrations of R667 and then for 3 days in the additional absence or presence of transforming growth factor-β1 (TGF-β1; 1 ng/ml). Cell lysates were then prepared and subjected to immunoblot analysis with antibodies to phosphorylated (p-) or total forms of focal adhesion kinase (FAK). The abundance of β-actin was examined as an internal control. B: Immunoblots similar to those in (A) were subjected to densitometric analysis to determine the intensity of each band for phosphorylated FAK relative to that of the corresponding band for FAK. Data are means ± standard deviation (SD) from three independent experiments. *p<0.01 versus the corresponding value for cells cultured without TGF-β1; †p<0.05 versus the corresponding value for cells cultured with TGF-β1 alone (the Tukey-Kramer test).