Histone acetyltransferase activity coactivators

Coactivators enhancing the transcriptional activity of steroid hormone receptors activators include SRC-1 (steroid-receptor co-activator 1) or TEF2 (transcriptional intermediary factor 2), which are recruited by the DNA/ steroid hormone receptor complex. Their main role is to attract other transcriptional coactivators with histone acetyltransferase activity in order to decondense chromatin and allow for the binding of components of the general transcription apparatus. 

Thompson, P.R., Kurooka, H., Nakatani, Y. and Cole, P.A. (2001) Transcriptional coactivator protein p300. Kinetic characterization of its histone acetyltransferase activity. The Journal of Biological Chemistry, 276, 33721-33729. 

Recently, other transcriptional coactivators harboring histone acetyltransferase activity, namely SRC-1/pi60, were demonstrated to enhance hypoxic stimulation (74). This complex also includes the bifunctional Ref-1 protein (74). These protein factors seem to act synergisticaUy with CBP. 

Benkirane M, Chun RF, Xiao H, Ogryzko VV, Howard BH, Nakatani Y, Jeang KT (1998) Activation of integrated provirus requires histone acetyltransferase. p300 and P/CAF are coactivators for HIV-1 Tat. J Biol Chem 273(38) 24898-24905... 

Bariev NA, Liu L, Chehab NH, Mansfield K, Harris KG, Halazonetis TD, Berger SL (2001) Acetylation of p53 activates transcription through recruitment of coactivators/histone acetyltransferases. Mol Cell 8 1243-1254... 

The effects of DNA-binding transactivators on Pol II are mediated by coactivator protein complexes such as TFIID or mediator. The modular structures of the transactivators have distinct activation and DNA-binding domains. Other protein complexes, including histone acetyltransferases such as GCN5-ADA2-ADA3 and ATP-dependent complexes such as SWI/SNF and NURF, reversibly remodel chromatin structure. 

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