NF-κB

Rel/NF-κB proteins are dimeric, DNA sequence-specific transcription factors that coordinate inflammatory responses; innate and adaptive immunity; and cellular differentiation, proliferation, and survival in almost all multicellular organisms. In most cells NF-κB exists in the cytoplasm in an inactive complex bound to IkappaB. The NF-κB network consists of five family member protein monomers (p65/RelA, RelB, cRel, p50, and p52) that form homodimers or heterodimers that bind DNA differentially and are regulated by two pathways: the canonical, NF-κB essential modulator (NEMO)-dependent pathway and the noncanonical, NEMO-independent pathway.

The I Bs bind to NF-κB dimers and sterically block the function of their NLSs, thereby causing their cytoplasmic retention. Potent NF-κB activators, such as TNFα and IL-1, cause almost complete degradation of IκBs (especially I B ) by the 26S proteasome, and NF-κB is activated and enters the nucleus. Nfkb2/p100 is the primary signaling node at which canonical and noncanonical signals interact. NIK/IKK1 processes p100 into p52, enabling the activity of RelB, NIK degrades IκBδ, allowing for sustained RelA activity, and canonical pathway activity may boost noncanonical pathway activation of RelB:p52.

Activation of the NF-κB pathway is involved in the pathogenesis of chronic inflammatory diseases, such as asthma, rheumatoid arthritis, and inflammatory bowel disease. In addition, altered NF-κB regulation may be involved in other diseases such as atherosclerosis and Alzheimer’s disease and a variety of human cancers. Therefore, numerous drugs, natural products, and normal or recombinant proteins that inhibits NF-κB activation can used in the treatment of NF-κB-related diseases.

References:
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[3] Mitchell S, et al. Wiley Interdiscip Rev Syst Biol Med. 2016 May;8(3):227-41.