This entry represents the interlocking domain of various eukaryotic nuclear receptor coactivators, including CREBP, P300, Ncoa1, Ncoa2 and Ncoa3. The interlocking domain forms a 3-helical non-globular array that forms interlocked heterodimers with its target.
Nuclear receptors are ligand-activated transcription factors involved in the regulation of many processes, including development, reproduction and homeostasis. Nuclear receptor coactivators act to modulate the function of nuclear receptors. Coactivators associate with promoters and enhancers primarily through protein-protein contacts to facilitate the interaction between DNA-bound transcription factors and the transcription machinery. Many of these coactivators are structurally related, including CBP (CREB-binding protein), P300 and ACTR (activator for thyroid and retinoid receptors) . CBP and P300 both have histone acetyltransferase activity . CBP/P300 proteins function synergistically to activate transcription, acting to remodel chromatin and to recruit RNA polymerase II and the basal transcription machinery. CBP is required for proper cell cycle control, differentiation and apoptosis. The interaction of CBP/P300 with transcription factors involves several small domains. The IBiD domain in the C-terminal of CBP is responsible for CBP interaction with IRF-3, as well as with the adenoviral oncoprotein E1A, TIF-2 coactivator, and the IRF homologue KSHV IRF-1 .
Ncoa1, Ncoa2 and Ncoa3 are all coactivators of various nuclear receptors. In addition, Ncoa1 and Ncoa3 both have histone acetyltransferase activity, but Ncoa2 does not [14757047, 15145939].