| Structural highlights
Disease
[NCOA1_HUMAN] Note=A chromosomal aberration involving NCOA1 is a cause of rhabdomyosarcoma. Translocation t(2;2)(q35;p23) with PAX3 generates the NCOA1-PAX3 oncogene consisting of the N-terminus part of PAX3 and the C-terminus part of NCOA1. The fusion protein acts as a transcriptional activator. Rhabdomyosarcoma is the most common soft tissue carcinoma in childhood, representing 5-8% of all malignancies in children.
Function
[NR1H3_HUMAN] Orphan receptor. Interaction with RXR shifts RXR from its role as a silent DNA-binding partner to an active ligand-binding subunit in mediating retinoid responses through target genes defined by LXRES. LXRES are DR4-type response elements characterized by direct repeats of two similar hexanuclotide half-sites spaced by four nucleotides. Plays an important role in the regulation of cholesterol homeostasis, regulating cholesterol uptake through MYLIP-dependent ubiquitination of LDLR, VLDLR and LRP8 (By similarity). [NCOA1_HUMAN] Nuclear receptor coactivator that directly binds nuclear receptors and stimulates the transcriptional activities in a hormone-dependent fashion. Involved in the coactivation of different nuclear receptors, such as for steroids (PGR, GR and ER), retinoids (RXRs), thyroid hormone (TRs) and prostanoids (PPARs). Also involved in coactivation mediated by STAT3, STAT5A, STAT5B and STAT6 transcription factors. Displays histone acetyltransferase activity toward H3 and H4; the relevance of such activity remains however unclear. Plays a central role in creating multisubunit coactivator complexes that act via remodeling of chromatin, and possibly acts by participating in both chromatin remodeling and recruitment of general transcription factors. Required with NCOA2 to control energy balance between white and brown adipose tissues. Required for mediating steroid hormone response. Isoform 2 has a higher thyroid hormone-dependent transactivation activity than isoform 1 and isoform 3.[1] [2] [3] [4] [5] [6] [7]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Liver X receptors (LXRs) are nuclear receptors that are central regulators of cholesterol homeostasis, and synthetic LXR agonists have shown promise as promoters of reverse cholesterol transport and anti-inflammatory agents. Here, we present three X-ray structures of three different agonists bound to the ligand binding domain of LXRalpha. These compounds are GW3965, F(3)methylAA, and a benzisoxazole urea, and we show that these diverse chemical scaffolds address common structural themes, leading to high binding affinity for LXR. Our structures show the LXRalpha ligand binding domain in its homodimeric form, an arrangement previously thought to be stereochemically difficult. A comparison with existing structures of the LXRbeta homodimer and LXRalpha:RXR (retinoid X receptor) heterodimers explains differences in dimer affinity and leads us to propose a model for allosteric activation in nuclear receptor dimers, in which an unactivated RXR partner provides an inhibitory tail wrap to the cofactor binding pocket of LXR.
X-ray structures of the LXRalpha LBD in its homodimeric form and implications for heterodimer signaling.,Fradera X, Vu D, Nimz O, Skene R, Hosfield D, Wynands R, Cooke AJ, Haunso A, King A, Bennett DJ, McGuire R, Uitdehaag JC J Mol Biol. 2010 May 28;399(1):120-32. Epub 2010 Apr 9. PMID:20382159[8]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Kalkhoven E, Valentine JE, Heery DM, Parker MG. Isoforms of steroid receptor co-activator 1 differ in their ability to potentiate transcription by the oestrogen receptor. EMBO J. 1998 Jan 2;17(1):232-43. PMID:9427757 doi:10.1093/emboj/17.1.232
- ↑ Onate SA, Tsai SY, Tsai MJ, O'Malley BW. Sequence and characterization of a coactivator for the steroid hormone receptor superfamily. Science. 1995 Nov 24;270(5240):1354-7. PMID:7481822
- ↑ Hayashi Y, Ohmori S, Ito T, Seo H. A splicing variant of Steroid Receptor Coactivator-1 (SRC-1E): the major isoform of SRC-1 to mediate thyroid hormone action. Biochem Biophys Res Commun. 1997 Jul 9;236(1):83-7. PMID:9223431 doi:10.1006/bbrc.1997.6911
- ↑ Spencer TE, Jenster G, Burcin MM, Allis CD, Zhou J, Mizzen CA, McKenna NJ, Onate SA, Tsai SY, Tsai MJ, O'Malley BW. Steroid receptor coactivator-1 is a histone acetyltransferase. Nature. 1997 Sep 11;389(6647):194-8. PMID:9296499 doi:10.1038/38304
- ↑ Jenster G, Spencer TE, Burcin MM, Tsai SY, Tsai MJ, O'Malley BW. Steroid receptor induction of gene transcription: a two-step model. Proc Natl Acad Sci U S A. 1997 Jul 22;94(15):7879-84. PMID:9223281
- ↑ Liu Z, Wong J, Tsai SY, Tsai MJ, O'Malley BW. Steroid receptor coactivator-1 (SRC-1) enhances ligand-dependent and receptor-dependent cell-free transcription of chromatin. Proc Natl Acad Sci U S A. 1999 Aug 17;96(17):9485-90. PMID:10449719
- ↑ Litterst CM, Kliem S, Marilley D, Pfitzner E. NCoA-1/SRC-1 is an essential coactivator of STAT5 that binds to the FDL motif in the alpha-helical region of the STAT5 transactivation domain. J Biol Chem. 2003 Nov 14;278(46):45340-51. Epub 2003 Sep 3. PMID:12954634 doi:http://dx.doi.org/10.1074/jbc.M303644200
- ↑ Fradera X, Vu D, Nimz O, Skene R, Hosfield D, Wynands R, Cooke AJ, Haunso A, King A, Bennett DJ, McGuire R, Uitdehaag JC. X-ray structures of the LXRalpha LBD in its homodimeric form and implications for heterodimer signaling. J Mol Biol. 2010 May 28;399(1):120-32. Epub 2010 Apr 9. PMID:20382159 doi:10.1016/j.jmb.2010.04.005
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