Inactivation of IKK but not JNK by SNAP in vitro. (A) C10 cells were exposed to 10 ng/ml TNFα for 5 min to induce IKK activity. Immunoprecipiated IKK was then exposed to indicated concentrations of SNAP for 15 min, and an in vitro kinase assay was performed by using GST-IκB as a substrate. IB, Western blotting for IKKγ.(B) C10 cells were treated with 10 ng/ml TNFα for 15 min to activate JNK, and JNK1 was immunoprecipitated from lysates. After a 15-min exposure to the indicated concentrations of SNAP or GSNO, an in vitro kinase assay was performed by using GST-c-Jun as a substrate. IB, Western blotting for JNK1.