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- The USA-Derived Transcriptional Coactivator PC2 Is a Submodu...The USA-Derived Transcriptional Coactivator PC2 Is a Submodule of TRAP/SMCC and Acts Synergistically with Other PCs
Molecular Cell, Volume 5, Issue 4, 1 April 2000, Pages 753-760
Sohail Malik, Wei Gu, Weizhen Wu, Jun Qin and Robert G Roeder
SummaryPC2, the high–molecular weight constituent of the potent USA transcriptional coactivator fraction, was identified as a Mediator-like complex. Its composition resembles that of the TRAP/SMCC complex, but PC2 is distinguished by the prominent absence of the SRB10 and SRB11 kinase/cyclin pair, as well as several additional polypeptides. Furthermore, affinity-purified PC2, which lacks independent activity, acts in synergy with USA-derived coactivators PC3/topoisomerase I and PC4 to mediate the effects of a variety of activators (including VP16, the synthetic activator GAL4-AH, and the orphan nuclear receptor HNF4) and thus recapitulates partial USA coactivator function.
Summary | Full Text | PDF (217 kb) - A Novel Human SRB/MED-Containing Cofactor Complex, SMCC, Inv...A Novel Human SRB/MED-Containing Cofactor Complex, SMCC, Involved in Transcription Regulation
Molecular Cell, Volume 3, Issue 1, 1 January 1999, Pages 97-108
Wei Gu, Sohail Malik, Mitsuhiro Ito, Chao-Xing Yuan, Joseph D Fondell, Xiaolong Zhang, Ernest Martinez, Jun Qin and Robert G Roeder
SummaryA novel human complex that can either repress activator-dependent transcription mediated by PC4, or, at limiting TFIIH, act synergistically with PC4 to enhance activator-dependent transcription has been purified. This complex contains homologs of a subset of yeast mediator/holoenzyme components (including SRB7, SRB10, SRB11, MED6, and RGR1), homologs of other yeast transcriptional regulatory factors (SOH1 and NUT2), and, significantly, some components (TRAP220, TRAP170/hRGR1, and TRAP100) of a human thyroid hormone receptor-associated coactivator complex. The complex shows direct activator interactions but, unlike yeast mediator, can act independently of the RNA polymerase II CTD. These findings demonstrate both positive and negative functional capabilities for the human complex, emphasize novel (CTD-independent) regulatory mechanisms, and link the complex to other human coactivator complexes.
Summary | Full Text | PDF (431 kb) - Identity between TRAP and SMCC Complexes Indicates Novel Pat...Identity between TRAP and SMCC Complexes Indicates Novel Pathways for the Function of Nuclear Receptors and Diverse Mammalian Activators
Molecular Cell, Volume 3, Issue 3, 1 March 1999, Pages 361-370
Mitsuhiro Ito, Chao-Xing Yuan, Sohail Malik, Wei Gu, Joseph D Fondell, Soichiro Yamamura, Zheng-Yuan Fu, Xiaolong Zhang, Jun Qin and Robert G Roeder
SummaryThe human thyroid hormone receptor–associated protein (TRAP) complex, an earlier described coactivator for nuclear receptors, and an SRB- and MED-containing cofactor complex (SMCC) that mediates activation by Gal4-p53 are shown to be virtually the same with respect to specific polypeptide subunits, coactivator functions, and mechanisms of action (activator interactions). In parallel with ligand-dependent interactions of nuclear receptors with the TRAP220 subunit, p53 and VP16 activation domains interact directly with a newly cloned TRAP80 subunit. These results indicate novel pathways for the function of nuclear receptors and other activators (p53 and VP16) through a common coactivator complex that is likely to target RNA polymerase II. Identification of the TRAP230 subunit as a previously predicted gene product also suggests a coactivator-related transcription defect in certain disease states.
Summary | Full Text | PDF (318 kb) - …more
Copyright © 2004 Cell Press. All rights reserved.
Molecular Cell, Volume 14, Issue 5, 685-691, 4 June 2004
doi:10.1016/j.molcel.2004.05.006
Short article
A Set of Consensus Mammalian Mediator Subunits Identified by Multidimensional Protein Identification Technology
Shigeo Sato1, 4, Chieri Tomomori-Sato1, 4, Tari J Parmely1, 4, Laurence Florens1, Boris Zybailov1, Selene K Swanson1, Charles A.S Banks1, Jingji Jin1, Yong Cai1, Michael P Washburn1, Joan Weliky Conaway*, 1, 2, 3, 
and Ronald C Conaway1, 2
1 Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110 USA
2 Department of Biochemistry and Molecular Biology, Kansas University Medical Center, Kansas City, KS 66160 USA
3 Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73190 USA
Correspondence: Joan Weliky Conaway, (816) 926-4091 (phone), (816) 926-2093 (fax)4 These authors contributed equally to this work.
Summary
The Mediator is a multiprotein transcriptional coactivator that is expressed ubiquitously in eukaryotes from yeast to mammals and is required for induction of RNA polymerase II (pol II) transcription by DNA binding transcription factors. In the work described here, we exploit multidimensional protein identification technology (MudPIT) to carry out a proteomic analysis of the subunit composition of the mammalian Mediator complex. By comparing MudPIT data sets obtained from six independent Mediator preparations immunoaffinity purified through their Nut2 (MED10), Med25 (MED9), Intersex (MED29), LCMR1 (MED19), AK007855 (MED28), or CRSP70 (MED26) subunits, we identify a set of consensus mammalian Mediator subunits. In addition, we identify as Mediator-associated proteins the CDK8-like cyclin-dependent kinase CDK11 and the TRAP240-like KIAA1025 protein (MED13L), which is mutated in patients with the congenital heart defect transposition of the great arteries (TGA).
