FIG. 1.

Effects of dominant negative forms of TAK1 and TAB2 on RANK-induced NF-κB activation. (A) 293 cells were transiently transfected with pNFκB-Luc, pRSV-β-gal, and the RANK expression plasmid along with indicated amounts of ΔTRAF6, TAK1(K63W), MEKK1KN, TAB2C, or MyD88C expression plasmids. Twenty-four hours later the cells were harvested, lysed, and assayed for luciferase expression. Luciferase activity was normalized to β-galactosidase activity resulting from the cotransfected β-galactosidase gene. Data are expressed as percentages of induction. Values shown above columns represent the fold increase relative to cells transfected with vector alone. (B) 293 cells were transfected with HA-JNK and RANK expression plasmid with TAB2C, TAK1(K63W), or MyD88C expression plasmids, as indicated. After 24 h, cell lysates were immunoprecipitated with anti-HA antibody, and immunoprecipitates were subjected to in vitro kinase assays with GST-c-Jun as a substrate (upper panel). Expression levels of Myc-RANK and HA-JNK were determined by immunoblotting with anti-Myc and anti-HA antibodies (middle and lower panels).