The unliganded mineralocorticoid receptor is associated with heat shock proteins 70 and 90 and the immunophilin FKBP-52.

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Bruner KL, Derfoul A, Robertson NM, Guerriero G, Fernandes-Alnemri T, Alnemri ES, Litwack G

The unliganded mineralocorticoid receptor is associated with heat shock proteins 70 and 90 and the immunophilin FKBP-52.

Recept Signal Transduct. 1997;7(2):85-98.

PubMed ID

9392437 [ View in PubMed

]

Abstract

The human mineralocorticoid receptor (MR) is a member of the steroid-thyroid hormone receptor superfamily, which includes receptors for retinoic acid, vitamin D, and other steroids, such as the glucocorticoids (which bind the glucocorticoid receptor, GR). MR and GR, the corticosteroid receptors, share significant homology and are activated by steroid binding, resulting in a conformational change, nuclear translocation, and DNA binding. Despite these similarities with GR, the MR remains less well characterized. However, protein components known to be present in the unliganded GR are also likely to be components of the heteromeric MR complex. In the current study, we investigated whether or not hsp70, hsp90, and the immunophilin FKBP-52 are present in the nonsteroid-bound MR complex, because these proteins are known to be present in the unliganded GR complex. The unliganded MR complex was assembled in vitro using reticulocyte lysate and in vivo using the baculovirus overexpression system and Spodoptera frugiperda (Sf9) cells. Western blot analysis revealed the presence of hsp70, hsp90, and FKBP-52 in the unliganded complexes, but hsp90 and FKBP-52 were not detected following exposure to aldosterone. Electrophoretic mobility shift analysis demonstrated that DNA binding of MR occurred only after treatment with aldosterone. These studies indicate that proteins associated with the unliganded GR are also present in the unliganded MR complex, and that hsp90 and FKBP-52 dissociate prior to DNA binding in a manner similar to that described for GR. Finally, the stoichiometric analysis of the proteins present within the heteromeric MR complex suggests a divergence between this receptor and the GR.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Aldosterone	Mineralocorticoid receptor	Protein	Humans	Unknown	Agonist	Details

Polypeptides

Name	UniProt ID
Mineralocorticoid receptor	P08235	Details