| Structural highlights
Function
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.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11]
Publication Abstract from PubMed
The 1.3-megadalton transcription factor IID (TFIID) is required for preinitiation complex (PIC) assembly and RNA polymerase II (Pol II)-mediated transcription initiation on almost all genes. The 26-subunit Mediator stimulates transcription and cyclin-dependent kinase 7 (CDK7)-mediated phosphorylation of the Pol II C-terminal domain (CTD). We determined the structures of human Mediator in the Tail module-extended (at near-atomic resolution) and Tail-bent conformations and structures of TFIID-based PIC-Mediator (76 polypeptides, ~4.1 megadaltons) in four distinct conformations. PIC-Mediator assembly induces concerted reorganization (Head-tilting and Middle-down) of Mediator and creates a Head-Middle sandwich, which stabilizes two CTD segments and brings CTD to CDK7 for phosphorylation; this suggests a CTD-gating mechanism favorable for phosphorylation. The TFIID-based PIC architecture modulates Mediator organization and TFIIH stabilization, underscoring the importance of TFIID in orchestrating PIC-Mediator assembly.
Structures of the human Mediator and Mediator-bound preinitiation complex.,Chen X, Yin X, Li J, Wu Z, Qi Y, Wang X, Liu W, Xu Y Science. 2021 Jun 4;372(6546):eabg0635. doi: 10.1126/science.abg0635. Epub 2021 , May 6. PMID:33958484[12]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ 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
- ↑ Chen X, Yin X, Li J, Wu Z, Qi Y, Wang X, Liu W, Xu Y. Structures of the human Mediator and Mediator-bound preinitiation complex. Science. 2021 Jun 4;372(6546):eabg0635. PMID:33958484 doi:10.1126/science.abg0635
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