| Structural highlights
Function
[VDR_RAT] Nuclear hormone receptor. Transcription factor that mediates the action of vitamin D3 by controlling the expression of hormone sensitive genes. Regulates transcription of hormone sensitive genes via its association with the WINAC complex, a chromatin-remodeling complex. Recruited to promoters via its interaction with the WINAC complex subunit BAZ1B/WSTF, which mediates the interaction with acetylated histones, an essential step for VDR-promoter association. Plays a central role in calcium homeostasis.[1] [MED1_HUMAN] Component of the Mediator complex, a coactivator involved in the regulated transcription of nearly all RNA polymerase II-dependent genes. Mediator functions as a bridge to convey information from gene-specific regulatory proteins to the basal RNA polymerase II transcription machinery. Mediator is recruited to promoters by direct interactions with regulatory proteins and serves as a scaffold for the assembly of a functional preinitiation complex with RNA polymerase II and the general transcription factors.[2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12]
Publication Abstract from PubMed
The secondary bile acid lithocholic acid (LCA) and its derivatives act as selective modulators of the vitamin D receptor (VDR), although their structures fundamentally differ from that of the natural hormone 1alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3). Here, we have determined the crystal structures of the ligand binding domain of rat VDR (VDR-LBD) in ternary complexes with a synthetic partial peptide of the coactivator MED1 (Mediator of RNA polymerase II transcription subunit 1) and four ligands, LCA, 3-keto LCA, LCA acetate, and LCA propionate, with the goal of elucidating their agonistic mechanism. LCA and its derivatives bind to the same ligand-binding pocket (LBP) of VDR-LBD that 1,25(OH)2D3 binds to, but in the opposite orientation; their A-ring is positioned at the top of the LBP, whereas their acyclic tail is located at the bottom of the LBP. However, most of the hydrophobic and hydrophilic interactions observed in the complex with 1,25(OH)2D3 are reproduced in the complexes with LCA and its derivatives. Additional interactions between VDR-LBD and the C-3 substituents of the A-ring are also observed in the complexes with LCA and its derivatives. These may result in the observed difference in the potency among the LCA-type ligands.
Crystal structures of complexes of vitamin D receptor ligand-binding domain with lithocholic acid derivatives.,Masuno H, Ikura T, Morizono D, Orita I, Yamada S, Shimizu M, Ito N J Lipid Res. 2013 May 30. PMID:23723390[13]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
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- ↑ Yuan CX, Ito M, Fondell JD, Fu ZY, Roeder RG. The TRAP220 component of a thyroid hormone receptor- associated protein (TRAP) coactivator complex interacts directly with nuclear receptors in a ligand-dependent fashion. Proc Natl Acad Sci U S A. 1998 Jul 7;95(14):7939-44. PMID:9653119
- ↑ Zhang J, Fondell JD. Identification of mouse TRAP100: a transcriptional coregulatory factor for thyroid hormone and vitamin D receptors. Mol Endocrinol. 1999 Jul;13(7):1130-40. PMID:10406464
- ↑ Wang Q, Sharma D, Ren Y, Fondell JD. A coregulatory role for the TRAP-mediator complex in androgen receptor-mediated gene expression. J Biol Chem. 2002 Nov 8;277(45):42852-8. Epub 2002 Sep 5. PMID:12218053 doi:10.1074/jbc.M206061200
- ↑ Ge K, Guermah M, Yuan CX, Ito M, Wallberg AE, Spiegelman BM, Roeder RG. Transcription coactivator TRAP220 is required for PPAR gamma 2-stimulated adipogenesis. Nature. 2002 May 30;417(6888):563-7. PMID:12037571 doi:10.1038/417563a
- ↑ Kang YK, Guermah M, Yuan CX, Roeder RG. The TRAP/Mediator coactivator complex interacts directly with estrogen receptors alpha and beta through the TRAP220 subunit and directly enhances estrogen receptor function in vitro. Proc Natl Acad Sci U S A. 2002 Mar 5;99(5):2642-7. Epub 2002 Feb 26. PMID:11867769 doi:10.1073/pnas.261715899
- ↑ Coulthard VH, Matsuda S, Heery DM. An extended LXXLL motif sequence determines the nuclear receptor binding specificity of TRAP220. J Biol Chem. 2003 Mar 28;278(13):10942-51. Epub 2003 Jan 29. PMID:12556447 doi:10.1074/jbc.M212950200
- ↑ Wallberg AE, Yamamura S, Malik S, Spiegelman BM, Roeder RG. Coordination of p300-mediated chromatin remodeling and TRAP/mediator function through coactivator PGC-1alpha. Mol Cell. 2003 Nov;12(5):1137-49. PMID:14636573
- ↑ Wu Q, Burghardt R, Safe S. Vitamin D-interacting protein 205 (DRIP205) coactivation of estrogen receptor alpha (ERalpha) involves multiple domains of both proteins. J Biol Chem. 2004 Dec 17;279(51):53602-12. Epub 2004 Oct 5. PMID:15471764 doi:10.1074/jbc.M409778200
- ↑ Malik S, Guermah M, Yuan CX, Wu W, Yamamura S, Roeder RG. Structural and functional organization of TRAP220, the TRAP/mediator subunit that is targeted by nuclear receptors. Mol Cell Biol. 2004 Sep;24(18):8244-54. PMID:15340084 doi:10.1128/MCB.24.18.8244-8254.2004
- ↑ Zhang X, Krutchinsky A, Fukuda A, Chen W, Yamamura S, Chait BT, Roeder RG. MED1/TRAP220 exists predominantly in a TRAP/ Mediator subpopulation enriched in RNA polymerase II and is required for ER-mediated transcription. Mol Cell. 2005 Jul 1;19(1):89-100. PMID:15989967 doi:10.1016/j.molcel.2005.05.015
- ↑ Udayakumar TS, Belakavadi M, Choi KH, Pandey PK, Fondell JD. Regulation of Aurora-A kinase gene expression via GABP recruitment of TRAP220/MED1. J Biol Chem. 2006 May 26;281(21):14691-9. Epub 2006 Mar 30. PMID:16574658 doi:M600163200
- ↑ Masuno H, Ikura T, Morizono D, Orita I, Yamada S, Shimizu M, Ito N. Crystal structures of complexes of vitamin D receptor ligand-binding domain with lithocholic acid derivatives. J Lipid Res. 2013 May 30. PMID:23723390 doi:10.1194/jlr.M038307
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