Figure 5.

IKK is necessary for NF-κB nuclear translocation and IκBα degradation induced by IR but not by UV-C. (A) HeLa cells grown on coverslips were transfected with an expression vector encoding HA-IKKβ (KA). After 36 hr the cells were exposed to the indicated stimuli or left untreated (−) and fixed. Samples were then incubated with a mixture of anti-p65 (RelA) and anti-HA. After washing, samples were stained with rhodamine-conjugated goat anti-rabbit IgG, fluorescein isothiocyanate-conjugated goat anti-mouse IgG-IgM, and Hoechst dye and photographed through an epifluorescence-equipped microscope. Arrowheads indicate cells that express HA-IKKβ (KA). (B) HeLa cells were transfected with an expression vector encoding HA-IκBα together with an empty vector or with a vector encoding HA-IKKβ (KA). Twenty-four hours later, cells were left untreated (C) or treated with IR, UV, or TNF. After 2 hr, 4 hr, or 15 min, cells were harvested and lysates were analyzed by immunoblotting with anti-HA.