NKIRAS1: Proteins and Enzymes

NF-kB is silenced in the cytoplasm by an inhibitory protein, IkB. Synthesis of IkBa is autoregulated. IkB proteins are phosphorylated by IkB kinase complex consisting of at least three proteins, IKK1/a, IKK2/b, and IKK3/g. 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. Six members of IkB family members have been identified. One of the first genes induced following NF-kB activation is IkBa. Recently, two proteins, kB-Ras1 and kB-Ras2 have been identified. These two proteins interact with PEST domains of IkBa and IkBb and decrease their rate of degradation.