Fig. 4. (a) siRNA targeting PAK1 or control siRNA oligos were transfected into keratinocytes. Following expression of constitutively active Rac1 (0.5 mg/ml) for 7 hours, siRNA-treated keratinocytes were stained for E-cadherin and the FLAG-tag. Scale bar, 20 µm. (b) Lysates were obtained and probed with antibodies against PAK1, actin and E-cadherin. (c) The rescue of Rac-dependent junction disruption by depletion of endogenous PAK was quantified using the ratio between cadherin staining and junction length (see Materials and Methods). ^*P<0.05.