Functional Interaction of the c-Myc Transactivation Domain with the TATA Binding Protein:  Evidence for an Induced Fit Model of Transactivation Domain Folding

McEwan, Iain J.; Dahlman-Wright, Karin; Ford, Jacqueline; Wright, Andrew N.

doi:10.1021/bi960793v

Cited by 101 publications

(99 citation statements)

References 80 publications

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“…As the ACID-TAD interaction is nevertheless tight and specific, this suggests that the activator might adopt multiple conformations on the same target surface. Such conformational flexibility is consistent with the general observation that activators form structured segments only transiently upon interaction with their targets through induced folding of helical segments 23,50 .…”

Section: Discussionsupporting

confidence: 88%

Structure and VP16 binding of the Mediator Med25 activator interaction domain

Vojnic

Mourão

Seizl

et al. 2011

Nat Struct Mol Biol

112

161

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4 0 4 VOLUME 18 NUMBER 4 APRIL 2011 nAture structurAl & moleculAr biologyActivator proteins regulate eukaryotic RNA polymerase II (Pol II) transcription in response to developmental and environmental signals. They bind to the DNA recognition sites of target genes with a sequence-specific DNA-binding domain, and recruit components of the Pol II machinery through a transcriptional activation domain (TAD) 1,2 . Activators have been classified as acidic, glutamine-rich, proline-rich and serine/threonine-rich, depending on the preponderance of amino acids in their TAD 3 . An archetypal acidic activator is the herpes simplex virus protein 16 (VP16), which activates the expression of immediate early viral genes during infection 4-8 . VP16 exerts its activating function through a C-terminal TAD that includes residues 413-490 (refs. 9-13). The VP16 TAD has been intensely used for studying transcriptional activation. Usually, the VP16 TAD is fused with its N terminus to the DNA-binding domain of the yeast transcription factor Gal4. The resulting Gal4-VP16 activator fusion protein stimulates transcription from promoters that contain Gal4-binding sites in the yeast and mammalian transcription systems in vivo 14,15 and in vitro 16,17 . This indicates that basic mechanisms of transcription activation are conserved amongst eukaryotes. The VP16 TAD targets basal Pol II transcription factors, including TFIIA, TFIIB, TFIID, the TFIIH subunit Tfb1/p62 (yeast/human) and the Mediator co-activator [18][19][20][21][22][23] . The VP16 TAD binds the Mediator subunit Med25 (also called Arc92) [24][25][26][27] , which is specific to higher eukaryotes. Med25 consists of two domains, the activator interaction domain (ACID) 24 that binds the VP16 TAD, and a 'von Willebrand factor type A' domain that anchors Med25 to Mediator 24 . Mediator generally conveys regulatory information by forming a bridge between activators and the basal Pol II machinery 28,29 . Whereas information on the core Mediator structure is emerging, structural information about its more peripheral activator-binding domains is limited to the KIX domain in subunit Med15 (or Arc105) 30,31 .The VP16 TAD is intrinsically flexible, whereas the VP16 core domain (residues 49-402) forms a stable structure 23,[32][33][34] . The TAD contains two functional subdomains, H1 (residues 410-452) and H2 (residues 453-490), which activate transcription independently 35,36 . Both H1 and H2 contain acidic amino acids, but specific bulky hydrophobic and aromatic residues are required for their function [36][37][38][39] . H2 has been proposed to adopt an α-helical conformation when bound to TFIIB 40 . NMR analysis revealed a nine-residue amphipathic α-helix in H2 that docks onto a PH fold in Tfb1 21 . On the basis of these and other results it is assumed that acidic TADs are flexible in their free state, but become transiently structured upon interaction with their target proteins.Here we report the NMR structure of the Mediator Med25 ACID and analyze its structural and functional interaction wi...

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Section: Discussionsupporting

confidence: 88%

Structure and VP16 binding of the Mediator Med25 activator interaction domain

Vojnic

Mourão

Seizl

et al. 2011

Nat Struct Mol Biol

112

161

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“…TBP has a central role in the basal transcription machinery and is involved in binding to a number of transcriptional activators (21,22,25,28). These multiprotein interactions may help to efficiently recruit TBP to the TATA box.…”

Section: Discussionmentioning

confidence: 99%

“…Models ii and iii may not be mutually exclusive, and we have shown previously that binding to a glucocorticoid response element induces a folded configuration in the GR NTD (24). Recent studies have shown that several transactivation domains undergo a transition to a folded state upon interaction with coregulatory proteins, which included some steroid receptors (25)(26)(27)(28). The question remaining is, does induced fit occur when the AF1 domain encounters a proper binding partner protein?…”

mentioning

confidence: 99%

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TATA box binding protein induces structure in the recombinant glucocorticoid receptor AF1 domain

Kumar

Volk

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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A number of transcription factor proteins contain domains that are fully or partially unstructured. The means by which such proteins acquire naturally folded conformations are not well understood. When they encounter their proper binding partner(s), several of these proteins adopt a folded conformation through an induced-fit mechanism. The glucocorticoid receptor (GR) is a ligand-activated transcription factor. Expressed independently as a recombinant peptide, the N-terminal transactivation domain (AF1) of the GR shows little structure and appears to exist as a collection of random coil configurations. The GR AF1 is known to interact with other transcription factors, including a critical component of the general transcription machinery proteins, the TATA box binding protein (TBP). We tested whether this interaction can lead to acquisition of structure in the GR AF1. Our results show that recombinant GR AF1 acquires a significant amount of helical content when it interacts with TBP. These structural changes were monitored by Fourier transform infrared and NMR spectroscopies, and by proteolytic digestions. Our results support a model in which TBP binding interaction with the GR AF1 induces significantly greater helical structure in the AF1 domain. This increased helical content in the GR AF1 appears to come mostly at the expense of random coil conformation. These results are in accordance with the hypothesis that an induced-fit mechanism gives structure to the GR AF1 when it encounters TBP.glucocorticoid receptor ͉ N-terminal activation function ͉ coregulatory protein ͉ protein folding T he glucocorticoid receptor (GR) is a ligand-activated transcription factor with the domain structural arrangement typical of the nuclear hormone receptors superfamily (1-4). The GR regulates transcription of target genes by binding DNA at specific hormone response elements and͞or by interacting with other transcription factors (5-8). Although the structural organization of steroid receptors into N-terminal domain (NTD), DNA binding domain (DBD), and ligand binding domain is well characterized (9-14), precisely how transcription is regulated by them is largely unknown. For all steroid receptors, this is in part due to the lack of information about their transcription activating domain AF1, located in the NTD (9, 10). The GR AF1 sequence resembles those of acidic transactivation domains of several transcription factors (15, 16). When expressed independently, the GR AF1 shows little structure and seems to exist as an ensemble of largely unstructured conformers (17, 18). The GR AF1 is known to interact with other transcription factors, and conditional folding has been suggested to be the key for these interactions (19)(20)(21)(22).It has been reported that in the presence of trifluoroethanol, the ''core'' of AF1 (AF1 c , amino acids 187-242), located toward the C-terminal end of AF1, adopts three helical segments (17). Independent experiments have shown that substitution of the ␣-helixbreaking amino acid proline for natural residues a...

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“…In contrast, loading of P-TEFb, TFIIH, and Mediator increased at these promoters in response to c-Myc (24). Several earlier studies have shown association of c-Myc with TATA box-binding protein (TBP) through direct binding (25)(26)(27)(28), providing another plausible mechanism for c-Myc to regulate gene expression. Indeed, substantial TBP recruitment by c-Myc is observed at pol I-transcribed rRNA genes (29).…”

mentioning

confidence: 98%

TRRAP and GCN5 are used by c-Myc to activate RNA polymerase III transcription

Kenneth

Ramsbottom

Gomez-Roman

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

107

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Activation of RNA polymerase (pol) II transcription by c-Myc generally involves recruitment of histone acetyltransferases and acetylation of histones H3 and H4. Here, we describe the mechanism used by c-Myc to activate pol III transcription of tRNA and 5S rRNA genes. Within 2 h of its induction, c-Myc appears at these genes along with the histone acetyltransferase GCN5 and the cofactor TRRAP. At the same time, occupancy of the pol III-specific factor TFIIIB increases and histone H3 becomes hyperacetylated, but increased histone H4 acetylation is not detected at these genes. The rapid acetylation of histone H3 and promoter assembly of TFIIIB, c-Myc, GCN5, and TRRAP are followed by recruitment of pol III and transcriptional induction. The selective acetylation of histone H3 distinguishes pol III activation by c-Myc from mechanisms observed in other systems.acetyltransferase ͉ chromatin ͉ histone ͉ TFIIIB ͉ TFIIIC

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Functional Interaction of the c-Myc Transactivation Domain with the TATA Binding Protein: Evidence for an Induced Fit Model of Transactivation Domain Folding

Cited by 101 publications

References 80 publications

Structure and VP16 binding of the Mediator Med25 activator interaction domain

Structure and VP16 binding of the Mediator Med25 activator interaction domain

TATA box binding protein induces structure in the recombinant glucocorticoid receptor AF1 domain

TRRAP and GCN5 are used by c-Myc to activate RNA polymerase III transcription

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