| Structural highlights
Function
RXRA_HUMAN Receptor for retinoic acid. Retinoic acid receptors bind as heterodimers to their target response elements in response to their ligands, all-trans or 9-cis retinoic acid, and regulate gene expression in various biological processes. The RAR/RXR heterodimers bind to the retinoic acid response elements (RARE) composed of tandem 5'-AGGTCA-3' sites known as DR1-DR5. The high affinity ligand for RXRs is 9-cis retinoic acid. RXRA serves as a common heterodimeric partner for a number of nuclear receptors. The RXR/RAR heterodimers bind to the retinoic acid response elements (RARE) composed of tandem 5'-AGGTCA-3' sites known as DR1-DR5. In the absence of ligand, the RXR-RAR heterodimers associate with a multiprotein complex containing transcription corepressors that induce histone acetylation, chromatin condensation and transcriptional suppression. On ligand binding, the corepressors dissociate from the receptors and associate with the coactivators leading to transcriptional activation. The RXRA/PPARA heterodimer is required for PPARA transcriptional activity on fatty acid oxidation genes such as ACOX1 and the P450 system genes.[1] [2] [3] [4]
Publication Abstract from PubMed
Retinoid X receptors (RXRs) play key roles in many physiological processes in both the periphery and central nervous system. In addition, RXRs form heterodimers with other nuclear receptors to exert their physiological effects. The nuclear receptor related 1 protein (NURR1) is particularly interesting because of its role in promoting differentiation and survival of dopamine neurons. However, only a small number of RXR-heterodimer selective modulators are available, with limited chemical diversity. This work describes the synthesis, biochemical evaluation, and structural elucidation of a novel series of RXR ligands with strongly biased interactions with RXRalpha-NURR1 heterodimers. Targeted modifications to the small molecule biaryl scaffold caused local RXRalpha side-chain disturbances and displacement of secondary structural elements upon ligand binding. This resulted in the repositioning of protein helices in the heterodimer interface of RXRalpha, alterations in homo- versus heterodimer formation, and modulation of activation function 2 (AF2). The data provide a rationale for the design of RXR ligands consisting of a highly conserved hydrophilic region, strongly contributing to the ligand affinity, and a variable hydrophobic region, which efficiently probes the effects of structural changes at the level of the ligand on co-regulator recruitment or the RXRalpha-NURR1 dimerization interface.
Ligand Dependent Switch from RXR Homo- to RXR-NURR1 Heterodimerization.,Scheepstra M, Andrei SA, de Vries RMJM, Meijer FA, Ma JN, Burstein ES, Olsson R, Ottmann C, Milroy LG, Brunsveld L ACS Chem Neurosci. 2017 Sep 20;8(9):2065-2077. doi: 10.1021/acschemneuro.7b00216., Epub 2017 Jul 24. PMID:28691794[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Gorla-Bajszczak A, Juge-Aubry C, Pernin A, Burger AG, Meier CA. Conserved amino acids in the ligand-binding and tau(i) domains of the peroxisome proliferator-activated receptor alpha are necessary for heterodimerization with RXR. Mol Cell Endocrinol. 1999 Jan 25;147(1-2):37-47. PMID:10195690
- ↑ Harish S, Ashok MS, Khanam T, Rangarajan PN. Serine 27, a human retinoid X receptor alpha residue, phosphorylated by protein kinase A is essential for cyclicAMP-mediated downregulation of RXRalpha function. Biochem Biophys Res Commun. 2000 Dec 29;279(3):853-7. PMID:11162439 doi:10.1006/bbrc.2000.4043
- ↑ Tsutsumi T, Suzuki T, Shimoike T, Suzuki R, Moriya K, Shintani Y, Fujie H, Matsuura Y, Koike K, Miyamura T. Interaction of hepatitis C virus core protein with retinoid X receptor alpha modulates its transcriptional activity. Hepatology. 2002 Apr;35(4):937-46. PMID:11915042 doi:10.1053/jhep.2002.32470
- ↑ Santos NC, Kim KH. Activity of retinoic acid receptor-alpha is directly regulated at its protein kinase A sites in response to follicle-stimulating hormone signaling. Endocrinology. 2010 May;151(5):2361-72. doi: 10.1210/en.2009-1338. Epub 2010 Mar , 9. PMID:20215566 doi:10.1210/en.2009-1338
- ↑ Scheepstra M, Andrei SA, de Vries RMJM, Meijer FA, Ma JN, Burstein ES, Olsson R, Ottmann C, Milroy LG, Brunsveld L. Ligand Dependent Switch from RXR Homo- to RXR-NURR1 Heterodimerization. ACS Chem Neurosci. 2017 Sep 20;8(9):2065-2077. doi: 10.1021/acschemneuro.7b00216., Epub 2017 Jul 24. PMID:28691794 doi:http://dx.doi.org/10.1021/acschemneuro.7b00216
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