Hepatic glucocorticoid receptor behaves differently when its hormone binding site is occupied by agonist (triamcinolone acetonide) or antagonist (RU486) steroid ligands

1991 ◽  
Vol 174 (3) ◽  
pp. 1239-1247 ◽  
Author(s):  
V.K. Moudgil ◽  
Madhavi Gunda
Keyword(s):  
Glucocorticoid Receptor ◽  
Binding Site ◽  
Triamcinolone Acetonide ◽  
Hormone Binding ◽  
Antagonist Ru486

Characterization of the glucocorticoid receptor in rat skin

1983 ◽  
Vol 96 (2) ◽  
pp. 229-239 ◽  
Author(s):  
Kenneth Smith ◽  
Sam Shuster ◽  
Michael Rawlins
Keyword(s):  
Glucocorticoid Receptor ◽  
Binding Site ◽  
Triamcinolone Acetonide ◽  
Rate Constant ◽  
Binding Sites ◽  
Proteolytic Enzymes ◽  
Specific Binding ◽  
Order Rate Constant ◽  
Rat Skin ◽  
Order Rate

Using an exchange assay to measure occupied and unoccupied binding sites the interaction between [3H]triamcinolone acetonide and rat skin cytosol proteins was studied. A binding site with a high affinity (dissociation constant = 7 × 10−10 mol/l) and a low capacity (400–600 fmol/mg protein) for triamcinolone acetonide was detected. The binding was specific to corticosteroids; fluorinated steroids showed a higher affinity than natural steroids. Non-corticosteroids, with the exception of progesterone, had little or no affinity for the binding site. At 0 °C the second-order rate constant of association was 2·23 × 106 mol/l per min and the first-order rate constant of dissociation was 1·6 × 10−4 per min. In the absence of dithiothreitol and molybdate the specific binding was rapidly abolished. The binding was also labile to heating and proteolytic enzymes. One day after adrenalectomy there was a significant increase in the number of assayable binding sites in the cytosol. The results are consistent with the binding protein being the physiological glucocorticoid receptor in rat skin.

scholarly journals Determinants for DNA-binding site recognition by the glucocorticoid receptor.

1992 ◽  
Vol 267 (35) ◽  
pp. 24941-24947
Author(s):  
J Zilliacus ◽  
A.P. Wright ◽  
U Norinder ◽  
J.A. Gustafsson ◽  
J Carlstedt-Duke
Keyword(s):  
Dna Binding ◽  
Glucocorticoid Receptor ◽  
Binding Site ◽  
Dna Binding Site ◽  
Site Recognition

Comparison between the human serum growth hormone-binding protein and the water-soluble growth hormone-binding site released from IM-9 lymphocytes

1993 ◽  
Vol 129 (6) ◽  
pp. 559-564 ◽  
Author(s):  
Guy Massa ◽  
Mapoko Ilondo ◽  
Magda Vanderschueren-Lodeweyckx
Keyword(s):  
Growth Hormone ◽  
Human Serum ◽  
Binding Site ◽  
Binding Protein ◽  
Water Soluble ◽  
Hormone Binding ◽  
Serum Growth Hormone ◽  
Gh Receptor ◽  
Growth Hormone Binding Protein ◽  
Hormone Binding Protein

The characteristics of the human serum growth hormone-binding protein (GHBP) were compared with those of a water-soluble GH-binding site prepared by incubating cultured IM-9 lymphocytes in assay buffer with 25 mmol/l iodoacetamide. High-performance liquid chromatography gel filtration of the water-soluble GH-binding site incubated with 125I-labeled human GH ([125I]hGH) revealed a large peak of bound [125I]hGH eluting at the same position as the peak of [125I]hGH bound to the GHBP in serum. The estimated Mr of the peak was 120 000, presumably representing one [125I]hGH bound to two binding sites. The binding specificities of the serum GHBP, the water-soluble GH-binding site and the GH receptor on IM-9 lymphocytes were identical. The binding affinities for 22 000 hGH and for 20 000 hGH of the serum GHBP were similar to the binding affinity of the water-soluble GH-binding site but lower than those of the cellular GH receptor. These findings show that the characteristics of the serum GHBP are comparable to those of the water-soluble GH-binding site released from IM-9 cells and support the hypothesis that in man the serum GHBP is produced by proteolytic cleavage of the cellular GH receptor.

scholarly journals Single-molecule force spectroscopy reveals folding steps associated with hormone binding and activation of the glucocorticoid receptor

2018 ◽  
Vol 115 (46) ◽  
pp. 11688-11693 ◽  
Author(s):  
Thomas Suren ◽  
Daniel Rutz ◽  
Patrick Mößmer ◽  
Ulrich Merkel ◽  
Johannes Buchner ◽  
...  
Keyword(s):  
Free Energy ◽  
Glucocorticoid Receptor ◽  
Ligand Binding ◽  
Optical Tweezers ◽  
Single Molecule ◽  
Mechanical Load ◽  
Force Spectroscopy ◽  
Folding Pathway ◽  
Hormone Binding ◽  
Single Molecule Force Spectroscopy

The glucocorticoid receptor (GR) is a prominent nuclear receptor linked to a variety of diseases and an important drug target. Binding of hormone to its ligand binding domain (GR-LBD) is the key activation step to induce signaling. This process is tightly regulated by the molecular chaperones Hsp70 and Hsp90 in vivo. Despite its importance, little is known about GR-LBD folding, the ligand binding pathway, or the requirement for chaperone regulation. In this study, we have used single-molecule force spectroscopy by optical tweezers to unravel the dynamics of the complete pathway of folding and hormone binding of GR-LBD. We identified a “lid” structure whose opening and closing is tightly coupled to hormone binding. This lid is located at the N terminus without direct contacts to the hormone. Under mechanical load, apo-GR-LBD folds stably and readily without the need of chaperones with a folding free energy of 41 kBT (24 kcal/mol). The folding pathway is largely independent of the presence of hormone. Hormone binds only in the last step and lid closure adds an additional 12 kBT of free energy, drastically increasing the affinity. However, mechanical double-jump experiments reveal that, at zero force, GR-LBD folding is severely hampered by misfolding, slowing it to less than 1·s−1. From the force dependence of the folding rates, we conclude that the misfolding occurs late in the folding pathway. These features are important cornerstones for understanding GR activation and its tight regulation by chaperones.

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