NF-κ-B is a pleiotropic transcription factor which is present in almost all cell types and is involved in many biological processed such as inflammation, immunity, differentiation, cell growth, tumorigenesis and apoptosis. NF-κ-B is a homo- or heterodimeric complex formed by the Rel-like domain-containing proteins RELA/p65, RELB, NFKB1/p105, NFKB1/p50, REL and NFKB2/p52 and the heterodimeric p65-p50 complex appears to be most abundant one. The dimers bind at kappa-B sites in the DNA of their target genes and the individual dimers have distinct preferences for different kappa-B sites that they can bind with distinguishable affinity and specificity. Different dimer combinations act as transcriptional activators or repressors, respectively. NF-κ-B is controlled by various mechanisms of post-translational modification and subcellular compartmentalization as well as by interactions with other cofactors or corepressors. NF-κ-B complexes are held in the cytoplasm in an inactive state complexed with members of the NF-κ-B inhibitor (I-kappa-B) family. In a conventional activation pathway, I-kappa-B is phosphorylated by I-kappa-B kinases (IKKs) in response to different activators, subsequently degraded thus liberating the active NF-κ-B complex which translocates to the nucleus. NF-κ-B heterodimeric p65-p50 and p65-c-Rel complexes are transcriptional activators. The NF-κ-B p65-p65 complex appears to be involved in invasin-mediated activation of IL-8 expression. The inhibitory effect of I-kappa-B upon NF-κ-B the cytoplasm is exerted primarily through the interaction with p65. p65 shows a weak DNA-binding site which could contribute directly to DNA binding in the NF-κ-B complex1) Xu C, et al (2005) Oncogene:24 (28): 4486-95. McNulty SE, et al. (2004) Pigment Cell Res Apr; 17 (2): 173-80. Madrid LV, et al. (2001) J Biol Chem: 276 (22): 18934-40. Wang D, et al. (2000) J Biol Chem : 275 (42): 32592-7.
More
|
