Keratinocytes were exposed to increasing doses of UVB and incubated for the indicated time. Cell lysates were harvested and proteins were detected by Western blot with the indicated antibodies. The band intensities were determined by densitometry and the fold change of proteins normalized to GAPDH is indicated. Panels A, B, D and E are representative blots from at least 3 independent experiments. (A) 308 cells and (D) NHEKs were sham irradiated or exposed to 500 J/m2 UVB and incubated for 4, 8, or 24 hrs. (B) 308 cells and (E) NHEKs were sham irradiated or exposed to 250, 500, or 1000 J/m2 UVB and incubated for 8 hrs. The mean fold change from sham of N-terminally unphosphorylated β-catenin (unphospho-β-catenin), total β-catenin and COX-2 for (C) 308 cells and (F) NHEKs was determined. *, P < 0.05.