Fig 7.

The IKK-related kinases phosphorylate mouse Act1 at Ser 147, Ser 209, and Ser 222. Flag-tagged mTBK1 (top) or mIKKi (middle) were expressed and immunoprecipitated from HEK293T cells and incubated with recombinant mouse Act1 (mAct1) deletion mutants or point mutants with changes of the mAct1 region of aa 121 to 390 as indicated. The incorporated radioactivity was detected by autoradiography. The recombinant GST fusion proteins of Act1 mutants were checked by Coomassie blue staining (CB) (bottom). The arrows indicate the autophosphorylation bands of IKK-related kinases. Stars indicate phosphorylated Act1. Asterisks indicate target protein.