(A) Traf6−/− MEFs resconstituted with either vector or TRAF6 (WT) and its mutants (K124R, C70A) were treated with IL-17, followed by Western with indicated antibodies. (B) Traf6−/− MEFs resconstituted with either vector or TRAF6 (WT) and its mutants (K124R, C70A) were subjected to NFκB luciferase assay. (C) and (D) GST-TRAF6 and its mutants (K124R, C70A) were used as substrates in the ubiquitination assays, followed by Western with antibodies against TRAF6 (C) and ubiquitin (D). [The results of real-time PCR and ELISA are calculated from five independent experiments. Group differences were calculated by t test * P < 0.05.]