NF-kB (nuclear factor kB) is sequestered in the cytoplasm by IkB family of inhibitory proteins that mask the nuclear localization signal of NF-kB thereby preventing translocation of NF-kB to the nucleus (1). External stimuli such as tumor necrosis factor or other cytokines results in phosphorylation and degradation of IkB releasing NF-kB dimers. NF-kB dimer subsequently translocates to the nucleus and activates target genes. Synthesis of IkBa is autoregulated (2). IkB proteins are phosphorylated by IkB kinase complex consisting of at least three proteins, IKK1/a, IKK2/b, and IKK3/g (3-7). IKK3/g preferentially interacts with IKK2/b and is required for activation of IKK complex. IKK3/g is also known as NEMO (NF-kB Essential Modulator) (7). Recent data suggest that the human T-cell leukemia virus type I Tax oncoprotein that activates NF-kB binds neither to IKKa nor IKKb, but complexes directly with IKKg (8,9). This suggests that IKKg may be a key molecule acting as an adapter for onco-protein specific signaling to IKKa and IKKb (8).