Figure 3. TAK1 inhibits transcription activity of SREBP.
HEK293 cells were transfected with the SREBP reporter (SRE-luciferase) and expression vectors for TAK1 (DsRed-TAK1) (A and C) or a kinase-dead form of TAK1 [TAK1(K63W)] (B and D) and mature forms of SREBP together with a constitutive promoter-driven renilla luciferase reporter. (A, B) The levels of transfected SREBPs and TAK1 were analyzed by immunoblotting. (C) SREBP-dependent transcriptional activity was determined by luciferase activity. Relative SREBP activity normalized to the protein levels of transfected SREBPs are shown. Means ± SD. n = 3; ***, p<0.001 (two-tailed unpaired Student’s t test). (D) SREBP-dependent transcriptional activity normalized to renilla luciferase activity is shown. Means ± SD ; n = 3; ***, p < 0.001 (one-way ANOVA).