Journal: The Journal of Biological Chemistry
Article Title: Analysis of Nuclear Factor-?B (NF-?B) Essential Modulator (NEMO) Binding to Linear and Lysine-linked Ubiquitin Chains and Its Role in the Activation of NF-?B *
doi: 10.1074/jbc.M112.347195
Figure Lengend Snippet: Linear di-ubiquitin is essential and sufficient to activate the IKK complex and NF-κB. A, linear di-ubiquitin and IKK complex induce phosphorylation of IκBα in vitro. Recombinant IKKα/β and NEMO (IKKγ) complex, MBP-IκBα-WT, or MBP-IκBα-AA, and linearly, Lys-63-, or Lys-48-linked di-ubiquitin were incubated as described under “Experimental Procedures.” Phosphorylation of MBP-IκBα by IKK was detected by immunoblotting. B, linear di-ubiquitin-fused NEMO induces sufficient NF-κB activity. HEK293T cells were transfected with increasing amounts (0.01, 0.03, 0.1, 0.3, and 1.0 μg) of FLAG-NEMO-[Ub]0–7 plasmids with NF-κB luciferase reporter, and the luciferase activity was measured 24 h after transfection. C, endogenous IKKα/β bound to linear di-ubiquitin-fused NEMO were phosphorylated. HEK293T cells, transfected with the indicated plasmids, were lysed and immunoprecipitated with anti-FLAG antibody. Immunoprecipitates were separated by SDS gels and immunoblotted with anti-phospho-IKKα/β and anti-IKKα/β antibodies. D, linear ubiquitin-fused NEMO-F312A mutant does not induce sufficient NF-κB activity. HEK293T cells were transfected with increasing amounts (0.01, 0.03, 0.1, 0.3, and 1.0 μg) of FLAG-NEMO-[Ub]0–4 plasmids with NF-κB luciferase reporter, and the luciferase activity was measured 24 h after transfection.
Article Snippet: Full-length murine NEMO and human IκBα-WT (amino acids 1–54) and IκBα-AA (amino acid 1–54 S34A/S36A) were cloned into pMAL-C2x (New England Biolabs).
Techniques: In Vitro, Recombinant, Incubation, Western Blot, Activity Assay, Transfection, Luciferase, Immunoprecipitation, Mutagenesis