K13 triggers the recruitment of p65, p50, and c-Rel to the CCL20 promoter. (A) An ELISA-based NF-κB binding assay showing increased binding of p65, p50, and c-Rel subunits in nuclear extracts derived from K13-expressing cells to the NF-κB site present in the CCL20 promoter. (B) K13 fails to activate CCL20 promoter in p65 and p50 knockout cells. WT and p65^−/− and p50^−/− MEFs were transfected with an empty vector or K13 along with a CCL20-WT-Luc (75 ng/well) and a Renilla reporter construct using Lipofectamine. The luciferase assay was performed 48 hours after transfection as described previously.³⁵