NF-kB Signaling Pathway
| PAG Title | NF-kB Signaling Pathway |
| PAG ID | WIG000386 |
| Type | P |
| Source Link |  MSigDB |
| Publication Reference | NA |
| PAG Description | Nuclear factor kB (NF-kB) is a nuclear transcription factor that regulates expression of a large number of genes that are critical for the regulation of apoptosis, viral replication, tumorigenesis, inflammation, and various autoimmune diseases. The activation of NF-kB is thought to be part of a stress response as it is activated by a variety of stimuli that include growth factors, cytokines, lymphokines, UV, pharmacological agents, and stress. In its inactive form, NF-kB is sequestered in the cytoplasm, bound by members of the IkB family of inhibitor proteins, which include IkBa, IkBb, IkBg, and IkBe. The various stimuli that activate NF-kB cause phosphorylation of IkB, which is followed by its ubiquitination and subsequent degradation. This results in the exposure of the nuclear localization signals (NLS) on NF-kB subunits and the subsequent translocation of the molecule to the nucleus. In the nucleus, NF-kB binds with a consensus sequence (5'GGGACTTTCC-3') of various genes and thus activates their transcription. IkB proteins are phosphorylated by IkB kinase complex consisting of at least three proteins; IKK1/IKKa, IKK2/IKKb, and IKK3/IKKg. These enzymes phosphorylate IkB leading to its ubiquitination and degradation. Tumor necrosis factor (TNF) which is the best-studied activator binds to its receptor and recruits a protein called TNF receptor death domain (TRADD). TRADD binds to the TNF receptor-associated factor 2 (TRAF-2) that recruits NF-kB-inducible kinase (NIK). Both IKK1 and IKK2 have canonical sequences that can be phosphorylated by the MAP kinase NIK/MEKK1 and both kinases can independently phosphorylate IkBa or IkBb. TRAF-2 also interacts with A20, a zinc finger protein whose expression is induced by agents that activate NF-kB. A20 functions to block TRAF2-mediated NF-kB activation. A20 also inhibits TNF and IL-1 induced activation of NF-kB suggesting that it may act as a general inhibitor of NF-kB activation. |
| Species | Homo sapiens |
| Quality Metric Scores | nCoCo Score: 9,164 |
| Information Content | Rich |
| Other IDs | M15285 |
| Base PAG ID | WIG000386 |
| Human Phenotyte Annotation | |
| Curator | PAGER curation team |
| Curator Contact | PAGER-contact@googlegroups.com |
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