Figure 5

JNK, as a downstream effector of PAK1, is essential for MMP-9 but not MMP-2 expression. (A) Normal HDFs, cultured on plastic or in 3D type-I collagen, were treated by cytokines together with inhibitors for p38 MAP kinase, JNK, and PI-3' kinase respectively at their effective concentrations. MMP-9 and -2 in the conditioned medium were detected by zymography. (B) HDFs transduced by lentivirus expressing GFP or PAK1 variant (K299R) were stimulated by cytokines for 20 min. JNK1/2 and the phosphorylated JNK were measured by Western blot analysis. (C) The levels of phosphorylated JNK1/2 were quantitated by densitometry analysis, and normalized by their protein levels. Data are the averages of three experiments.