The human androgen receptor AF1 transactivation domain: interactions with transcription factor IIF and molten-globule-like structural characteristics

2006 ◽  
Vol 34 (6) ◽  
pp. 1054-1057 ◽  
Author(s):  
D.N. Lavery ◽  
I.J. McEwan
Keyword(s):  
Transcription Factor ◽  
Androgen Receptor ◽  
Protein Interactions ◽  
Structural Characteristics ◽  
Molten Globule ◽  
Transactivation Domain ◽  
Protein Protein Interactions ◽  
Induced Folding ◽  
Transcription Factor Iif ◽  
Structural Aspects

The AR (androgen receptor) is a ligand-activated transcription factor and member of the steroid receptor superfamily. The AR responds to the ligands testosterone and dihydrotestosterone and activates multiple downstream genes required in development and reproduction. During the events of transactivation, the AR makes specific protein–protein interactions with several basal transcription factors such as TBP (TATA-box-binding protein) and TFIIF (transcription factor IIF). These interactions occur predominantly within a defined region termed AF1 (activation function-1) located within the highly disordered N-terminal domain of the receptor. Our focus is on the structural aspects of AF1 and how this flexible and disordered domain generates functional interactions with regulators of transcription. Our working hypothesis is that AR-AF1 domain exhibits induced folding when contacted by transcription regulators (such as TFIIF) into a more compact and ‘active’ conformation, enabling further co-regulator recruitment and ultimately transcription. Structural flexibility and intrinsic disorder of AR-AF1 were studied using predictive algorithms and fluorescence spectroscopy under different experimental conditions and the results revealed this domain retains characteristics indicative of molten-globule or pre-molten-globule-like structures. We hypothesize that this partially folded intermediate state is important for, and enables the AF1 domain to make, multiple protein–protein interactions. The structural aspects of AR-AF1 and interactions with TFIIF are discussed.

The androgen receptor transactivation domain: the interplay between protein conformation and protein–protein interactions

2003 ◽  
Vol 31 (5) ◽  
pp. 1042-1046 ◽  
Author(s):  
J. Reid ◽  
R. Betney ◽  
K. Watt ◽  
I.J. McEwan
Keyword(s):  
Androgen Receptor ◽  
Protein Interactions ◽  
Transcriptional Activation ◽  
Specific Protein ◽  
Transactivation Domain ◽  
Protein Protein Interactions ◽  
Induced Folding ◽  
Large N ◽  
Tryptophan Residues ◽  
Receptor Transactivation

The AR (androgen receptor) belongs to the nuclear receptor superfamily and directly regulates patterns of gene expression in response to the steroids testosterone and dihydrotestosterone. Sequences within the large N-terminal domain of the receptor have been shown to be important for transactivation and protein–protein interactions; however, little is known about the structure and folding of this region. Folding of the AR transactivation domain was observed in the presence of the helix-stabilizing solvent trifluorethanol and the natural osmolyte TMAO (trimethylamine N-oxide). TMAO resulted in the movement of two tryptophan residues to a less solvent-exposed environment and the formation of a protease-resistant conformation. Critically, binding to a target protein, the RAP74 subunit of the general transcription factor TFIIF, resulted in a similar resistance to protease digestion, consistent with induced folding of the receptor transactivation domain. Our current hypothesis is that the folding of the transactivation domain in response to specific protein–protein interactions creates a platform for subsequent interactions, resulting in the formation of a competent transcriptional activation complex.

New perceptions of transcription factor properties from NMR

1998 ◽  
Vol 76 (2-3) ◽  
pp. 368-378 ◽  
Author(s):  
Stefan Bagby ◽  
Cheryl H Arrowsmith ◽  
Mitsuhiko Ikura
Keyword(s):  
Transcription Factor ◽  
Protein Interactions ◽  
Dna Interaction ◽  
Protein Protein Interactions ◽  
Nmr Studies ◽  
X Ray ◽  
X Ray Crystallography ◽  
Protein Protein Interaction ◽  
Structural Problems ◽  
Induced Folding

The complementarity of NMR and X-ray crystallography for biomacromolecular studies has been particularly evident in analysis of transcription factor structures and interactions. While X-ray crystallography can be used to tackle relatively complicated structural problems including multicomponent (three and higher) complexes, NMR studies have provided new insights into the nature of protein-DNA and protein-protein interactions that would be difficult to obtain by other biophysical methods. We describe herein some of the novel and important information recently derived from NMR studies of transcription factors.Key words: protein-DNA interaction, protein-protein interaction, induced folding, conformational fluctuations, transcriptional regulation.

Molecular mechanisms of androgen receptor-mediated gene regulation: structure-function analysis of the AF-1 domain.

2004 ◽  
Vol 11 (2) ◽  
pp. 281-293 ◽  
Author(s):  
I J McEwan
Keyword(s):  
Androgen Receptor ◽  
Protein Interactions ◽  
Molecular Mechanisms ◽  
Function Analysis ◽  
Transactivation Domain ◽  
Protein Protein Interactions ◽  
Amino Terminal ◽  
Transcription Complexes ◽  
Amino Terminal Domain ◽  
General Transcription Machinery

The androgen receptor is a ligand-activated transcription factor that binds DNA response elements as a homodimer. Binding sites for the receptor have been identified both upstream and downstream of the transcription start site. Once bound to DNA, the receptor contacts chromatin remodelling complexes, coactivator proteins and components of the general transcription machinery in order to regulate target gene expression. The main transactivation domain, termed AF1, is located within the structurally distinct amino-terminal domain. This region is structurally flexible but adopts a more folded conformation in the presence of the binding partner TFIIF, and this in turn enhances subsequent protein-protein interactions. Thus, there is likely to be a dynamic interplay between protein-protein interactions and protein folding, involving AF1, that is proposed to lead to the assembly and/or disassembly of receptor-dependent transcription complexes.

scholarly journals SOX2 O-GlcNAcylation alters its protein-protein interactions and genomic occupancy to modulate gene expression in pluripotent cells

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Samuel A Myers ◽  
Sailaja Peddada ◽  
Nilanjana Chatterjee ◽  
Tara Friedrich ◽  
Kiichrio Tomoda ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Protein Interactions ◽  
Regulatory Mechanism ◽  
Embryonic Stem ◽  
Transactivation Domain ◽  
Wild Type ◽  
Protein Protein Interactions ◽  
Reprogramming Efficiency ◽  
Induction Of Differentiation

The transcription factor SOX2 is central in establishing and maintaining pluripotency. The processes that modulate SOX2 activity to promote pluripotency are not well understood. Here, we show SOX2 is O-GlcNAc modified in its transactivation domain during reprogramming and in mouse embryonic stem cells (mESCs). Upon induction of differentiation SOX2 O-GlcNAcylation at serine 248 is decreased. Replacing wild type with an O-GlcNAc-deficient SOX2 (S248A) increases reprogramming efficiency. ESCs with O-GlcNAc-deficient SOX2 exhibit alterations in gene expression. This change correlates with altered protein-protein interactions and genomic occupancy of the O-GlcNAc-deficient SOX2 compared to wild type. In addition, SOX2 O-GlcNAcylation impairs the SOX2-PARP1 interaction, which has been shown to regulate ESC self-renewal. These findings show that SOX2 activity is modulated by O-GlcNAc, and provide a novel regulatory mechanism for this crucial pluripotency transcription factor.

scholarly journals Glycyrrhizic Acid for COVID-19: Findings of Targeting Pivotal Inflammatory Pathways Triggered by SARS-CoV-2

2021 ◽  
Vol 12 ◽  
Author(s):  
Wenjiang Zheng ◽  
Xiufang Huang ◽  
Yanni Lai ◽  
Xiaohong Liu ◽  
Yong Jiang ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Protein Interactions ◽  
Glycyrrhizic Acid ◽  
Enrichment Analysis ◽  
Host Factors ◽  
Pathway Enrichment Analysis ◽  
Protein Protein Interactions ◽  
Health Crisis ◽  
Inflammatory Pathways ◽  
Anti Inflammatory

Background: Coronavirus disease 2019 (COVID-19) is now a worldwide public health crisis. The causative pathogen is severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Novel therapeutic agents are desperately needed. Because of the frequent mutations in the virus and its ability to cause cytokine storms, targeting the viral proteins has some drawbacks. Targeting cellular factors or pivotal inflammatory pathways triggered by SARS-CoV-2 may produce a broader range of therapies. Glycyrrhizic acid (GA) might be beneficial against SARS-CoV-2 because of its anti-inflammatory and antiviral characteristics and possible ability to regulate crucial host factors. However, the mechanism underlying how GA regulates host factors remains to be determined.Methods: In our report, we conducted a bioinformatics analysis to identify possible GA targets, biological functions, protein-protein interactions, transcription-factor-gene interactions, transcription-factor-miRNA coregulatory networks, and the signaling pathways of GA against COVID-19.Results: Protein-protein interactions and network analysis showed that ICAM1, MMP9, TLR2, and SOCS3 had higher degree values, which may be key targets of GA for COVID-19. GO analysis indicated that the response to reactive oxygen species was significantly enriched. Pathway enrichment analysis showed that the IL-17, IL-6, TNF-α, IFN signals, complement system, and growth factor receptor signaling are the main pathways. The interactions of TF genes and miRNA with common targets and the activity of TFs were also recognized.Conclusions: GA may inhibit COVID-19 through its anti-oxidant, anti-viral, and anti-inflammatory effects, and its ability to activate the immune system, and targeted therapy for those pathways is a predominant strategy to inhibit the cytokine storms triggered by SARS-CoV-2 infection.

scholarly journals The 14-3-3 Proteins as Important Allosteric Regulators of Protein Kinases

2020 ◽  
Vol 21 (22) ◽  
pp. 8824
Author(s):  
Veronika Obsilova ◽  
Tomas Obsil
Keyword(s):  
Protein Interactions ◽  
Cell Cycle Progression ◽  
State Of The Art ◽  
Review Article ◽  
Protein Protein Interactions ◽  
Cycle Progression ◽  
Kinase Regulation ◽  
Functional Consequences ◽  
Allosteric Regulators ◽  
Structural Aspects

Phosphorylation by kinases governs many key cellular and extracellular processes, such as transcription, cell cycle progression, differentiation, secretion and apoptosis. Unsurprisingly, tight and precise kinase regulation is a prerequisite for normal cell functioning, whereas kinase dysregulation often leads to disease. Moreover, the functions of many kinases are regulated through protein–protein interactions, which in turn are mediated by phosphorylated motifs and often involve associations with the scaffolding and chaperon protein 14-3-3. Therefore, the aim of this review article is to provide an overview of the state of the art on 14-3-3-mediated kinase regulation, focusing on the most recent mechanistic insights into these important protein–protein interactions and discussing in detail both their structural aspects and functional consequences.

Interactions in vivo between the proteins of infectious bursal disease virus: capsid protein VP3 interacts with the RNA-dependent RNA polymerase, VP1

Microbiology ◽  
2000 ◽  
Vol 81 (1) ◽  
pp. 209-218 ◽  
Author(s):  
Mirriam G. J. Tacken ◽  
Peter J. M. Rottier ◽  
Arno L. J. Gielkens ◽  
Ben P. H. Peeters
Keyword(s):  
Disease Virus ◽  
Protein Interactions ◽  
Infectious Bursal Disease Virus ◽  
Viral Proteins ◽  
Infectious Bursal Disease ◽  
Transactivation Domain ◽  
Protein Protein Interactions ◽  
Bursal Disease ◽  
Infected Cells

Little is known about the intermolecular interactions between the viral proteins of infectious bursal disease virus (IBDV). By using the yeast two-hybrid system, which allows the detection of protein–protein interactions in vivo, all possible interactions were tested by fusing the viral proteins to the LexA DNA-binding domain and the B42 transactivation domain. A heterologous interaction between VP1 and VP3, and homologous interactions of pVP2, VP3, VP5 and possibly VP1, were found by co-expression of the fusion proteins in Saccharomyces cerevisiae. The presence of the VP1–VP3 complex in IBDV-infected cells was confirmed by co-immunoprecipitation studies. Kinetic analyses showed that the complex of VP1 and VP3 is formed in the cytoplasm and eventually is released into the cell-culture medium, indicating that VP1–VP3 complexes are present in mature virions. In IBDV-infected cells, VP1 was present in two forms of 90 and 95 kDa. Whereas VP3 initially interacted with both the 90 and 95 kDa proteins, later it interacted exclusively with the 95 kDa protein both in infected cells and in the culture supernatant. These results suggest that the VP1–VP3 complex is involved in replication and packaging of the IBDV genome.

scholarly journals Structure and function of steroid receptor AF1 transactivation domains: induction of active conformations

2005 ◽  
Vol 391 (3) ◽  
pp. 449-464 ◽  
Author(s):  
Derek N. Lavery ◽  
Iain J. Mcewan
Keyword(s):  
Protein Interactions ◽  
Functional Model ◽  
Binding Domain ◽  
Protein Protein Interactions ◽  
Receptor Proteins ◽  
Signalling Molecules ◽  
Transactivation Domains ◽  
Induced Folding ◽  
Α Helix ◽  
And Function

Steroid hormones are important endocrine signalling molecules controlling reproduction, development, metabolism, salt balance and specialized cellular responses, such as inflammation and immunity. They are lipophilic in character and act by binding to intracellular receptor proteins. These receptors function as ligand-activated transcription factors, switching on or off networks of genes in response to a specific hormone signal. The receptor proteins have a conserved domain organization, comprising a C-terminal LBD (ligand-binding domain), a hinge region, a central DBD (DNA-binding domain) and a highly variable NTD (N-terminal domain). The NTD is structurally flexible and contains surfaces for both activation and repression of gene transcription, and the strength of the transactivation response has been correlated with protein length. Recent evidence supports a structural and functional model for the NTD that involves induced folding, possibly involving α-helix structure, in response to protein–protein interactions and structure-stabilizing solutes.

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