The transformed glucocorticoid receptor has a lower steroid-binding affinity than the nontransformed receptor

Journal Article · Tue Feb 20 04:00:00 EST 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00459a031· OSTI ID:6940773

Nemoto, Takayuki; Ohara-Nemoto, Yuko; Denis, M; Gustafsson, J A ^[1]

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1. Huddinge University Hospital (Sweden)

High-salt treatment of cytosolic glucocorticoid receptor (GR) preparations reduces the steroid-binding ability of the receptor and induces the conversion of the receptor from a nontransformed (non-DNA-binding) 9S form to a transformed (DNA-binding) 4S entity. Therefore, the authors decided to investigate the possible relationship between these two phenomena. The binding of ({sup 3}H)triamcinolone acetonide (({sup 3}H)TA) to the 9S form was almost saturated at a concentration of 20 nM, whereas ({sup 3}H)TA was hardly bound to the 4S form at this concentration. The 4S form was efficiently labeled at 200 nM. Scatchard analysis of the GR showed the presence of two types of binding sites. In the absence of molybdate, the ratio of the lower affinity site was increased, but the total number of binding sites was not modified. The GR with the low ({sup 3}H)TA-binding affinity bound to DNA-cellulose even in its unliganded state, whereas the form with the high affinity did not. These results indicate that the transformed GR has a reduced ({sup 3}H)TA-binding affinity as compared to the nontransformed GR. The steroid-binding domain (amino acids 477-777) and the DNA- and steroid-binding domains (amino acids 415-777) of the human GR were expressed in Escherichia coli as protein A fused proteins. Taken together, these results suggest that the component(s) associating with the nontransformed GR, possibly the heat shock protein hsp 90, play(s) an important role in stabilizing the GR in a high-affinity state for steroids.

• OSTI ID: 6940773
• Journal Information: Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 29:7; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ADRENAL HORMONES
ANIMALS
BIOCHEMICAL REACTION KINETICS
CORTICOSTEROIDS
DOSE-RESPONSE RELATIONSHIPS
ELECTROPHORESIS
GLUCOCORTICOIDS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
KETONES
KINETICS
MAMMALS
MAN
MEMBRANE PROTEINS
ORGANIC COMPOUNDS
PREGNANES
PRIMATES
PROTEINS
RADIORECEPTOR ASSAY
REACTION KINETICS
RECEPTORS
STEROIDS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES