| Structural highlights
Function
[TF65_HUMAN] NF-kappa-B is a pleiotropic transcription factor present in almost all cell types and is the endpoint of a series of signal transduction events that are initiated by a vast array of stimuli related to many biological processes such as inflammation, immunity, differentiation, cell growth, tumorigenesis and apoptosis. NF-kappa-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-kappa-B is controlled by various mechanisms of post-translational modification and subcellular compartmentalization as well as by interactions with other cofactors or corepressors. NF-kappa-B complexes are held in the cytoplasm in an inactive state complexed with members of the NF-kappa-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-kappa-B complex which translocates to the nucleus. NF-kappa-B heterodimeric p65-p50 and p65-c-Rel complexes are transcriptional activators. The NF-kappa-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-kappa-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-kappa-B complex. Associates with chromatin at the NF-kappa-B promoter region via association with DDX1.[1] [2] [3] [4] [5] [6]
Publication Abstract from PubMed
p65 is a member of the NF-kappaB family of transcriptional regulatory proteins that functions as the activating component of the p65-p50 heterodimer. Through its acidic transactivation domain (TAD), p65 has the capacity to form interactions with several different transcriptional regulatory proteins, including TFIIB, TFIIH, CREB-binding protein (CBP)/p300 and TAFII31. Like other acidic TADs, the p65 TAD contains two subdomains (p65TA1 and p65TA2) that interact with different regulatory factors depending on the target gene. Despite its role in controlling numerous NF-kappaB target genes, there are no high-resolution structures of p65TA1 bound to a target transcriptional regulatory factor. In this work, we characterize the interaction of p65TA1 with two factors, the Tfb1/p62 subunit of TFIIH and the KIX domain of CBP. In these complexes, p65TA1 transitions into a helical conformation that includes its characteristic PhiXXPhiPhi motif (Phi = hydrophobic amino acid). Structural and functional studies demonstrate that the two binding interfaces are primarily stabilized by three hydrophobic amino acids within the PhiXXPhiPhi motif and these residues are also crucial to its ability to activate transcription. Taken together, the results provide an atomic level description of how p65TA1 is able to bind different transcriptional regulatory factors needed to activate NF-kappaB target genes.
Structural characterization of interactions between transactivation domain 1 of the p65 subunit of NF-kappaB and transcription regulatory factors.,Lecoq L, Raiola L, Chabot PR, Cyr N, Arseneault G, Legault P, Omichinski JG Nucleic Acids Res. 2017 Feb 28. doi: 10.1093/nar/gkx146. PMID:28334776[7]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Schulte R, Grassl GA, Preger S, Fessele S, Jacobi CA, Schaller M, Nelson PJ, Autenrieth IB. Yersinia enterocolitica invasin protein triggers IL-8 production in epithelial cells via activation of Rel p65-p65 homodimers. FASEB J. 2000 Aug;14(11):1471-84. PMID:10928981
- ↑ Asamitsu K, Tetsuka T, Kanazawa S, Okamoto T. RING finger protein AO7 supports NF-kappaB-mediated transcription by interacting with the transactivation domain of the p65 subunit. J Biol Chem. 2003 Jul 18;278(29):26879-87. Epub 2003 May 13. PMID:12748188 doi:10.1074/jbc.M211831200
- ↑ Liu Y, Smith PW, Jones DR. Breast cancer metastasis suppressor 1 functions as a corepressor by enhancing histone deacetylase 1-mediated deacetylation of RelA/p65 and promoting apoptosis. Mol Cell Biol. 2006 Dec;26(23):8683-96. Epub 2006 Sep 25. PMID:17000776 doi:10.1128/MCB.00940-06
- ↑ Sun S, Tang Y, Lou X, Zhu L, Yang K, Zhang B, Shi H, Wang C. UXT is a novel and essential cofactor in the NF-kappaB transcriptional enhanceosome. J Cell Biol. 2007 Jul 16;178(2):231-44. Epub 2007 Jul 9. PMID:17620405 doi:jcb.200611081
- ↑ Ishaq M, Ma L, Wu X, Mu Y, Pan J, Hu J, Hu T, Fu Q, Guo D. The DEAD-box RNA helicase DDX1 interacts with RelA and enhances nuclear factor kappaB-mediated transcription. J Cell Biochem. 2009 Feb 1;106(2):296-305. doi: 10.1002/jcb.22004. PMID:19058135 doi:10.1002/jcb.22004
- ↑ Sharif-Askari E, Vassen L, Kosan C, Khandanpour C, Gaudreau MC, Heyd F, Okayama T, Jin J, Rojas ME, Grimes HL, Zeng H, Moroy T. Zinc finger protein Gfi1 controls the endotoxin-mediated Toll-like receptor inflammatory response by antagonizing NF-kappaB p65. Mol Cell Biol. 2010 Aug;30(16):3929-42. doi: 10.1128/MCB.00087-10. Epub 2010 Jun , 14. PMID:20547752 doi:10.1128/MCB.00087-10
- ↑ Lecoq L, Raiola L, Chabot PR, Cyr N, Arseneault G, Legault P, Omichinski JG. Structural characterization of interactions between transactivation domain 1 of the p65 subunit of NF-kappaB and transcription regulatory factors. Nucleic Acids Res. 2017 Feb 28. doi: 10.1093/nar/gkx146. PMID:28334776 doi:http://dx.doi.org/10.1093/nar/gkx146
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