Figure 5

Elevated IKK activity in MyoD^-/-myoblasts is responsible for increased NF-κB activity. (A) Kinase assay (KA): IKK was immunoprecipitated from protein extracts of WT (MyoD^+/+) and MyoD^-/- primary myoblasts, and assayed for kinase activity using GST-IκBα and γ-³²P-ATP as substrate. Immunoblot (IB): IKK was immunoprecipitated from protein extracts of WT (MyoD^+/+) and MyoD^-/- primary myoblasts, and assayed by western blot using an antibody specific for IKKγ. (B) MyoD^-/- myoblasts were transfected with vector control, vector expressing a dominant negative mutant IKKβ (IKKβ DN) or a non-phosphorylatable mutant of IkBα (IκB-SR), in addition to an NF-κB reporter (3xκB-Luc). Bars represent average luciferase activity (relative light units (RLUs)) (n = 3). Error bars represent standard deviation.