scholarly journals The nuclear bile acid receptor FXR is activated by PGC-1α in a ligand-dependent manner

2004 ◽  
Vol 382 (3) ◽  
pp. 913-921 ◽  
Author(s):  
Eiko KANAYA ◽  
Takuma SHIRAKI ◽  
Hisato JINGAMI
Keyword(s):  
Bile Acid ◽  
Ligand Binding ◽  
Transcriptional Activation ◽  
Expression System ◽  
Binding Domain ◽  
Ligand Binding Domain ◽  
Farnesoid X Receptor ◽  
Dependent Manner ◽  
Acid Receptor ◽  
Bile Acid Receptor

The nuclear bile acid receptor FXR (farnesoid X receptor) is one of the key factors that suppress bile acid biosynthesis in the liver. PGC-1α [PPARγ (peroxisome-proliferator-activated receptor γ) co-activator-1α] is known to control energy homoeostasis in adipose tissue, skeletal muscle and liver. We performed cell-based reporter assays using the expression system of a GAL4–FXR chimaera, the ligand-binding domain of FXR fused to the DNA-binding domain of yeast GAL4, to find the co-activators for FXR. We found that the transcriptional activation of a reporter plasmid by a GAL4–FXR chimaera was strongly enhanced by PGC-1α, in a ligand-dependent manner. Transcriptional activation of the SHP (small heterodimer partner) gene by the FXR–RXRα (retinoid X receptor α) heterodimer was also enhanced by PGC-1α in the presence of CDCA (chenodeoxycholic acid). Co-immunoprecipitation and pull-down studies using glutathione S-transferase–PGC-1α fusion proteins revealed that the ligand-binding domain of FXR binds PGC-1α in a ligand-influenced manner both in vivo and in vitro. Furthermore, our studies revealed that SHP represses its own transcription, and the addition of excess amounts of PGC-1α can overcome the inhibitory effect of SHP. These observations indicate that PGC-1α mediates the ligand-dependent activation of FXR and transcription of SHP gene.

The androgen receptor depends on ligand‐binding domain dimerization for transcriptional activation

EMBO Reports ◽  
2021 ◽  
Author(s):  
Sarah El Kharraz ◽  
Vanessa Dubois ◽  
Martin E Royen ◽  
Adriaan B Houtsmuller ◽  
Ekatarina Pavlova ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Ligand Binding ◽  
Transcriptional Activation ◽  
Binding Domain ◽  
Ligand Binding Domain

Glucose sensing O-GlcNAcylation pathway regulates the nuclear bile acid receptor farnesoid X receptor (FXR)

Hepatology ◽  
2014 ◽  
Vol 59 (5) ◽  
pp. 2022-2033 ◽  
Author(s):  
Wahiba Berrabah ◽  
Pierrette Aumercier ◽  
Céline Gheeraert ◽  
Hélène Dehondt ◽  
Emmanuel Bouchaert ◽  
...  
Keyword(s):  
Bile Acid ◽  
Glucose Sensing ◽  
Farnesoid X Receptor ◽  
Acid Receptor ◽  
Bile Acid Receptor

scholarly journals Introduction of Nonacidic Side Chains on 6-Ethylcholane Scaffolds in the Identification of Potent Bile Acid Receptor Agonists with Improved Pharmacokinetic Properties

Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1043 ◽  
Author(s):  
Claudia Finamore ◽  
Giuliana Baronissi ◽  
Silvia Marchianò ◽  
Francesco Di Leva ◽  
Adriana Carino ◽  
...  
Keyword(s):  
Bile Acid ◽  
Metabolic Disorders ◽  
Farnesoid X Receptor ◽  
Pharmacological Characterization ◽  
Acid Receptor ◽  
Pharmacokinetic Properties ◽  
Docking Calculations ◽  
Bile Acid Receptor ◽  
Receptor Modulators

As a cellular bile acid sensor, farnesoid X receptor (FXR) and the membrane G-coupled receptor (GPBAR1) participate in maintaining bile acid, lipid, and glucose homeostasis. To date, several selective and dual agonists have been developed as promising pharmacological approach to metabolic disorders, with most of them possessing an acidic conjugable function that might compromise their pharmacokinetic distribution. Here, guided by docking calculations, nonacidic 6-ethyl cholane derivatives have been prepared. In vitro pharmacological characterization resulted in the identification of bile acid receptor modulators with improved pharmacokinetic properties.

Expression of human all-trans-retinoic acid receptor β and its ligand-binding domain in Escherichia coli

1995 ◽  
Vol 308 (1) ◽  
pp. 353-359 ◽  
Author(s):  
M Berggren Söderlund ◽  
G Johannesson ◽  
G Fex
Keyword(s):  
Escherichia Coli ◽  
Retinoic Acid ◽  
Ligand Binding ◽  
Retinoic Acid Receptor ◽  
Binding Domain ◽  
Ligand Binding Domain ◽  
Acid Receptor ◽  
Recombinant Receptors ◽  
Trans Retinoic Acid ◽  
All Trans Retinoic Acid

all-trans-Retinoic acid, one of the hormonally active derivatives of vitamin A, occurs physiologically in plasma at a concentration below 10 nmol/l. The methods currently used for its quantification are based on HPLC, need about 1 ml of serum, are relatively laborious and thus not well suited for mass analysis. The affinity and specificity of retinoic acid receptors for all-trans-retinoic acid encouraged us to express both the entire human retinoic acid receptor beta (RAR-beta) and two versions of its retinoic acid-binding domain in Escherichia coli in the hope that these recombinant proteins might be used as binders in a ligand-binding assay for all-trans-retinoic acid. The recombinant receptors, the whole receptor [RAR-beta-(V7-Q448)], corresponding to domains A-F, and the ligand-binding domain [RAR-beta-(E149-Q448)], corresponding to domains D-F, were expressed in the vector pET 3d/BL21 (DE3) as inclusion bodies, solubilized with guanidinium chloride, renatured and purified by ion-exchange chromatography. RAR-beta-(P193-Q448), corresponding to domains E-F, was expressed in the vector pET 3d/BL21(DE3)pLysS, and purified by reversed-phase chromatography. Under non-denaturing conditions, the expressed whole receptor [RAR-beta-(V7-Q448)] and the D-F construct (RAR-beta-(E149-Q448)] behaved chromatographically as monomeric proteins whereas the E-F construct [RAR-beta-(P193-Q448)] had a strong tendency to aggregate. RAR-beta-(V7-Q448) and RAR-beta-(E149-Q448) had similar Kd values for all-trans-retinoic acid (1.4 and 0.6 nmol/l respectively) whereas RAR-beta-(P193-Q448) bound all-trans-retinoic acid less avidly (Kd 9.6 nmol/l). 9-cis-Retinoic acid bound to RAR-beta-(E149-Q448) and RAR-beta-(V7-Q448) as avidly as all-trans-retinoic acid. Competition experiments showed weak or no binding of 4-oxo-all-trans-retinoic acid, 4-oxo-13-cis-retinoic acid, 13-cis-retinoic acid, acitretin and retinol by RAR-beta-(E149-Q448).

scholarly journals Molecular Determinants of Glucocorticoid Receptor Mobility in Living Cells: the Importance of Ligand Affinity

2003 ◽  
Vol 23 (6) ◽  
pp. 1922-1934 ◽  
Author(s):  
Marcel J. M. Schaaf ◽  
John A. Cidlowski
Keyword(s):  
Dna Binding ◽  
Glucocorticoid Receptor ◽  
Ligand Binding ◽  
Conformational Change ◽  
Binding Domain ◽  
Ligand Binding Domain ◽  
Dependent Manner ◽  
Dna Binding Domain ◽  
Ligand Affinity ◽  
High Affinity

ABSTRACT The actions of glucocorticoids are mediated by the glucocorticoid receptor (GR), which is activated upon ligand binding, and can alter the expression of target genes either by transrepression or transactivation. We have applied FRAP (fluorescence recovery after photobleaching) to quantitatively assess the mobility of the yellow fluorescent protein (YFP)-tagged human GR α-isoform (hGRα) in the nucleus of transiently transfected COS-1 cells and to elucidate determinants of its mobility. Addition of the high-affinity agonist dexamethasone markedly decreases the mobility of the receptor in a concentration-dependent manner, whereas low-affinity ligands like corticosterone decrease the mobility to a much lesser extent. Analysis of other hGRα ligands differing in affinity suggests that it is the affinity of the ligand that is a major determinant of the decrease in mobility. Similar results were observed for two hGRα antagonists, the low-affinity antagonist ZK98299 and the high-affinity antagonist RU486. The effect of ligand affinity on mobility was confirmed with the hGRα mutant Q642V, which has an altered affinity for triamcinolone acetonide, dexamethasone, and corticosterone. Analysis of hGRα deletion mutants indicates that both the DNA-binding domain and the ligand-binding domain of the receptor are required for a maximal ligand-induced decrease in receptor mobility. Interestingly, the mobility of transfected hGRα differs among cell types. Finally, the proteasome inhibitor MG132 immobilizes a subpopulation of unliganded receptors, via a mechanism requiring the DNA-binding domain and the N-terminal part of the ligand-binding domain. Ligand binding makes the GR resistant to the immobilizing effect of MG132, and this effect depends on the affinity of the ligand. Our data suggest that ligand binding induces a conformational change of the receptor which is dependent on the affinity of the ligand. This altered conformation decreases the mobility of the receptor, probably by targeting the receptor to relatively immobile nuclear domains with which it transiently associates. In addition, this conformational change blocks immobilization of the receptor by MG132.

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