Fig. 3. Regulation of IKK during keratinocyte differentiation. (A) Luciferase assay showing the ability of p63 isoforms to transactivate IKK in HaCaT cells. The ratio IKK promoter to TAp63/Np63 isoforms was 1:2. Results are shown as mean ± s.d. of three independent experiments. (B) Quantitative real-time PCR performed on HaCaT cells induced to differentiate in high Ca²⁺ for 1 and 3 days. Np63 and K14 mRNA decreases indicating that the cells underwent differentiation. Results are shown as mean ± s.d. from three independent experiments. (C) Western blot using anti-IKK and anti-keratin 1-antibody (K1) on HaCaT cells induced to differentiate in high Ca²⁺ for 1 to 5 days. K1 is shown as control for keratinocyte differentiation; actin is shown as loading control. (D) Quantification of the western blot by densitometry.