BACKGROUND: Generalized glucocorticoid resistance is a rare condition characterized by partial, end-organ insensitivity to glucocorticoids, compensatory elevations in adrenocorticotropic hormone and cortisol secretion, and increased production of adrenal steroids with androgenic and/or mineralocorticoid activity. We have identified a new case of glucocorticoid resistance caused by a novel mutation of the human glucocorticoid receptor (hGR) gene and studied the molecular mechanisms through which the mutant receptor impairs glucocorticoid signal transduction. METHODS AND RESULTS: We identified a novel, single, heterozygous nucleotide (T --> C) substitution at position 2209 (exon 9alpha) of the hGR gene, which resulted in phenylalanine (F) to leucine (L) substitution at amino acid position 737 within helix 11 of the ligand-binding domain of the protein. Compared with the wild-type receptor, the mutant receptor hGRalphaF737L demonstrated a significant ligand-exposure time-dependent decrease in its ability to transactivate the glucocorticoid-inducible mouse mammary tumor virus promoter in response to dexamethasone and displayed a 2-fold reduction in the affinity for ligand, a 12-fold delay in nuclear translocation, and an abnormal interaction with the glucocorticoid receptor-interacting protein 1 coactivator. The mutant receptor preserved its ability to bind to DNA and exerted a dominant-negative effect on the wild-type hGRalpha only after a short duration of exposure to the ligand. CONCLUSIONS: The mutant receptor hGRalphaF737L causes generalized glucocorticoid resistance because of decreased affinity for the ligand, marked delay in nuclear translocation, and/or abnormal interaction with the glucocorticoid receptor-interacting protein 1 coactivator. These findings confirm the importance of the C terminus of the ligand-binding domain of the receptor in conferring transactivational activity.
BACKGROUND: Generalized glucocorticoid resistance is a rare condition characterized by partial, end-organ insensitivity to glucocorticoids, compensatory elevations in adrenocorticotropic hormone and cortisol secretion, and increased production of adrenal steroids with androgenic and/or mineralocorticoid activity. We have identified a new case of glucocorticoid resistance caused by a novel mutation of the humanglucocorticoid receptor (hGR) gene and studied the molecular mechanisms through which the mutant receptor impairs glucocorticoid signal transduction. METHODS AND RESULTS: We identified a novel, single, heterozygous nucleotide (T --> C) substitution at position 2209 (exon 9alpha) of the hGR gene, which resulted in phenylalanine (F) to leucine (L) substitution at amino acid position 737 within helix 11 of the ligand-binding domain of the protein. Compared with the wild-type receptor, the mutant receptor hGRalphaF737L demonstrated a significant ligand-exposure time-dependent decrease in its ability to transactivate the glucocorticoid-inducible mouse mammary tumor virus promoter in response to dexamethasone and displayed a 2-fold reduction in the affinity for ligand, a 12-fold delay in nuclear translocation, and an abnormal interaction with the glucocorticoid receptor-interacting protein 1 coactivator. The mutant receptor preserved its ability to bind to DNA and exerted a dominant-negative effect on the wild-type hGRalpha only after a short duration of exposure to the ligand. CONCLUSIONS: The mutant receptor hGRalphaF737L causes generalized glucocorticoid resistance because of decreased affinity for the ligand, marked delay in nuclear translocation, and/or abnormal interaction with the glucocorticoid receptor-interacting protein 1 coactivator. These findings confirm the importance of the C terminus of the ligand-binding domain of the receptor in conferring transactivational activity.
Authors: Michael L Roberts; Tomoshige Kino; Nicolas C Nicolaides; Darrell E Hurt; Eleni Katsantoni; Amalia Sertedaki; Filadelfia Komianou; Korina Kassiou; George P Chrousos; Evangelia Charmandari Journal: J Clin Endocrinol Metab Date: 2013-02-20 Impact factor: 5.958
Authors: Nicolas C Nicolaides; Michael L Roberts; Tomoshige Kino; Geoffrey Braatvedt; Darrell E Hurt; Eleni Katsantoni; Amalia Sertedaki; George P Chrousos; Evangelia Charmandari Journal: J Clin Endocrinol Metab Date: 2014-01-31 Impact factor: 5.958
Authors: Jonas W Højfeldt; Osvaldo Cruz-Rodríguez; Yasuhiro Imaeda; Aaron R Van Dyke; James P Carolan; Anna K Mapp; Jorge A Iñiguez-Lluhí Journal: Mol Endocrinol Date: 2014-01-01
Authors: Nicolas C Nicolaides; Zoi Galata; Tomoshige Kino; George P Chrousos; Evangelia Charmandari Journal: Steroids Date: 2009-10-07 Impact factor: 2.668