Sam Okret - Academia.edu (original) (raw)
Papers by Sam Okret
PubMed, 1984
Limited proteolysis of the glucocorticoid receptor has proven to be a valuable tool for a functio... more Limited proteolysis of the glucocorticoid receptor has proven to be a valuable tool for a functional analysis of the receptor protein. With the help of these analyses, it has been possible to describe three functional domains of the receptor protein. The native glucocorticoid-receptor complex contains a steroid-binding domain (A), a DNA-binding domain (B) and an immunoactive domain (C). This form of the glucocorticoid receptor has a Stokes radius of 6.1 nm and a molecular weight of 94 K when purified. Two steroid-binding proteolytic receptor fragments can be found. The larger one has a Stokes radius of 3.3 - 3.6 nm and a molecular weight of 39 K and contains both the steroid- and DNA-binding sites (A + B). The smaller steroid-binding receptor fragment, with a Stokes radius of 1.9 nm and a molecular weight of 27 K, contains only the steroid-binding domain (A). Analysis of the proteolytic fragments of the glucocorticoid receptor using the specific anti-receptor antibodies revealed the occurrence of a fragment with Stokes radius 2.6 nm following limited proteolysis of the receptor by alpha-chymotrypsin. This fragment contains neither the steroid-binding nor the DNA-binding domains but consists only of the immunoactive domain (C). Further proteolysis of this fragment results in an even smaller form with Stokes radius 1.4 nm. The apparent identity of the larger of the two proteolytic forms of the glucocorticoid receptor (the 3.3 - 3.6 nm form) with the receptor isolated from certain corticosteroid-resistant cells, together with the lack of the immunoreactive domain in these cells appears to indicate an important function of this domain with regard to the biological activity of the receptor.
PubMed, 1990
... 1990;322:65-80. Structure, function and regulation of the glucocorticoid receptor. Gustafsson... more ... 1990;322:65-80. Structure, function and regulation of the glucocorticoid receptor. Gustafsson JA, Carlstedt-Duke J, Strömstedt PE, Wikström AC, Denis M, Okret S, Dong Y. Department of Medical Nutrition, Karolinska Institute, Huddinge University Hospital F69, Sweden. ...
PubMed, Jul 1, 1983
Glucocorticoid-resistant (CR), in contrast to glucocorticoid-sensitive (CS), mouse lymphoma P1798... more Glucocorticoid-resistant (CR), in contrast to glucocorticoid-sensitive (CS), mouse lymphoma P1798 was shown to lack antiglucocorticoid receptor immunoactivity. Antibodies raised against the purified rat liver glucocorticoid receptor (GR) cross-reacted with the GR from CS, but not with the GR from CR, P1798 lymphoma. Using highly specific antisera against the GR in an indirect competitive enzyme-linked immunosorbent assay, it was demonstrated that alpha-chymotrypsin digestion of the GR from CS P1798 lymphoma caused a separation of a "resistant-like" nonimmunogenic steroid and DNA-binding domain (Stokes' radius, 3.3 nm) from an immunoactive domain (Stokes' radius, 2.6 nm). In contrast to CS P1798 lymphoma, neither before nor after alpha-chymotrypsin digestion, immunoactivity could be found in the cytosol from CR P1798 lymphoma. This was assayed after chromatography on DNA-cellulose or gel filtration on Agarose A (0.5 m). These results suggest that the domain of the CS GR containing the immunoactive determinant(s), normally removed by limited proteolysis by alpha-chymotrypsin, appears to be missing in CR P1798 lymphoma cytosol. It seems that this domain plays an important role in the mechanism of action of glucocorticoids. This might suggest that a mutation has occurred affecting the genome resulting in defective transcription of the receptor gene(s) in CR P1798 lymphoma.
Endocrinology, May 1, 1992
Monoclonal antibodies directed against four different polypeptide epitopes on the Mr approximatel... more Monoclonal antibodies directed against four different polypeptide epitopes on the Mr approximately 94,000 steroid-binding subunit of the rat liver cytosolic glucocorticoid receptor (GcR) were used to probe Western blots of epididymal spermatozoa from rats and mice. Two sperm polypeptides with apparent molecular weights of 94,000 (indistinguishable in size from the liver GcR subunit) and 150,000 reacted with these antibodies. Other polypeptides that are present in a wide variety of somatic cells [lamin-A, -B, and -C; topoisomerase-I; poly(ADP-ribose) polymerase; the 62-kilodalton internal nuclear matrix protein; the nucleolar protein B23; and histone H1] could not be detected in these preparations of spermatozoa, thus appearing to rule out contamination by somatic cells. Rat and mouse pachytene spermatocytes and round spermatids contained much lower amounts of the Mr approximately 94,000 and 150,000 polypeptides. These results suggested that the steroid-binding subunit of the GcR might be accumulated late in spermatogenesis. Consistent with this view, a 6-kilobase mRNA (identical in size to a mRNA detected in mouse somatic cell lines) was detected when Northern blots of mouse round spermatid RNA were probed with a cDNA to the steroid-binding GcR subunit. Although the results described above suggest the presence of GcR in rodent sperm, high affinity binding of glucocorticoids to epididymal sperm could not be detected in a whole cell binding assay. Further analysis revealed that the Mr approximately 90,000 heat shock protein (hsp90), a component reportedly required for high affinity ligand binding to the GcR, was present in early germ cells, but absent from rodent epididymal sperm. These results suggest that the Mr approximately 94,000 steroid-binding subunit of the GcR and an immunologically related Mr approximately 150,000 polypeptide are specifically accumulated during the later stages of rodent spermatogenesis, but are not assembled into receptor complexes capable of binding steroid. In addition, these results support the view that hsp90 is required for high affinity binding of glucocorticoids to the Mr approximately 94,000 GcR subunit in intact cells.
Biochimica et biophysica acta. Molecular cell research, Mar 1, 2009
Glucocorticoid (GC) effects are mediated via the GC-receptor (GR), which either stimulates or rep... more Glucocorticoid (GC) effects are mediated via the GC-receptor (GR), which either stimulates or represses gene expression. Repression of target genes often involves negative cross-talk between the GR and other transcription factors e.g. NF-kappaB, important for gene activation. Using HEK293 cells we here describe that repression of NF-kappaB requires functions of the GR that are dependent on the signaling pathways employed to activate NF-kappaB. While a GR mutant was able to repress NF-kappaB activity following activation by TNFalpha, it did not so following activation by the phorbol ester TPA. In these cells, TPA stimulation but not TNFalpha, activated extracellular signal-regulated kinase (ERK). We demonstrated that the ability of the dexamethasone activated GR mutant to repress TPA-induced NF-kappaB activity was restored in conjunction with ERK1/2 inhibition. Previous reports have shown GC-mediated inhibition of ERK1/2 phosphorylation to involve GC induction of MAPK phosphatase-1 (MKP-1). Here, we demonstrated that the GRR488Q mutant was incapable of inducing gene expression of endogenous MKP-1 following dexamethasone treatment, in contrast to the GRwt. However, TPA treatment alone resulted in much stronger MKP-1 expression in both GRwt and GRR488Q containing cells than that of dexamethasone suggesting that the inability of GRR488Q to inhibit TPA-induced NF-kappaB activity did not involve a lack of MKP-1 expression. In line with this, RNAi targeted towards MKP-1 did not abolish or inhibit the ability of the GRwt to repress NF-kappaB activity. Importantly, we observed no difference in activated ERK1/2 (phospho-ERK1/2) expression over time between GRwt and GRR488Q containing cells following co-treatment with TPA and dexamethasone. Based on these results we suggest that GRwt does not directly regulate ERK1/2 but rather alters ERK1/2-mediated effects allowing it to repress NF-kappaB activity, a capacity lacked by the GRR488Q mutant.
Journal of Biological Chemistry, Sep 1, 1986
The nuclear matrix is a putative skeletal structure which has been implicated in many nuclear fun... more The nuclear matrix is a putative skeletal structure which has been implicated in many nuclear functions. To assess a possible role of the nuclear matrix in glucocorticoid action, purified rat liver nuclei containing glucocorticoid-receptor complexes were treated with DNase I +/- RNase A followed by 1.6 M NaCl, thus yielding salt-extractable and salt-resistant (nuclear matrix) fractions. The subnuclear distribution of hormone-receptor complexes was determined by following the fate of unmetabolized radiolabel after injection of labeled triamcinolone acetonide into adrenalectomized animals and subjecting various subfractions to immunoblotting using a monoclonal antibody which recognizes the glucocorticoid receptor. Both techniques indicated that 50-70% of the total nuclear hormone-receptor complexes were recovered in the nuclear matrix fraction. Previous results (Kaufmann, S. H., and Shaper, J. H. (1984) Exp. Cell Res. 155, 477-495) suggest that a variety of nuclear polypeptides become nuclease- and salt-resistant as a result of the formation of intermolecular disulfide bonds. The following evidence suggests that disulfide bonds mediate the association between the glucocorticoid receptor and the nuclear matrix. When nuclei were isolated in the absence of sulfhydryl-blocking and -cross-linking reagents, sodium dodecyl sulfate-polyacrylamide gel electrophoresis under nonreducing conditions revealed that the receptor was present as a high molecular weight disulfide-cross-linked complex. When nuclei were isolated in the presence of the irreversible sulfhydryl-blocking reagent iodoacetamide, the disulfide bonds which cross-linked the receptor into high molecular weight complexes were absent; and 85-100% of the hormone-receptor complexes were salt-extractable. When nuclei (isolated in the absence of iodoacetamide) were treated with the sulfhydryl-cross-linking reagent sodium tetrathionate, greater than 95% of the nuclear hormone-receptor complexes became resistant to extraction with nucleases and 1.6 M NaCl. The implications of these results for other matrix-associated nuclear functions are discussed.
Endocrine Reviews, May 1, 1987
THE INTRACELLULAR receptor proteins for steroid hormones are a group of transcriptional regulator... more THE INTRACELLULAR receptor proteins for steroid hormones are a group of transcriptional regulatory proteins with several common features, acting by direct interaction with DNA. The protein must first be activated by the binding of the appropriate class of steroid. The ...
Nature, Dec 1, 1984
The effects of steroid hormones are mediated by intracellular hormone-specific receptor proteins;... more The effects of steroid hormones are mediated by intracellular hormone-specific receptor proteins; the interaction between the hormone and its receptor increases the affinity of the receptor for nuclear binding sites, thereby modulating the expression of specific genes. The glucocorticoid receptor is a soluble protein of relative molecular mass (Mr) 94,000 (94K), present at a low relative abundance (less than or equal to 0.01%); it has been purified to near-homogeneity, and specific antisera and monoclonal antibodies have been produced. Purified glucocorticoid receptor binds in vitro with high affinity to defined regions of DNA near regulated promoters, and sequences essential for these interactions are functional in vivo as hormone-dependent transcriptional enhancer elements. We have now cloned complementary DNA (cDNA) for the rat liver glucocorticoid receptor and we describe here a 2.6-kilobase (kb) receptor cDNA isolated following polysome immuno-enrichment of receptor messenger RNA with glucocorticoid receptor-specific antibodies. The receptor appears to be encoded by a single-copy gene which specifies a approximately 6-kb transcript in rat and mouse cells; this mRNA is altered quantitatively and qualitatively in several mutant cell lines with specific defects in receptor function.
Molecular Endocrinology, Dec 1, 1988
The mechanism of ligand-induced (homologous) down-regulation of the glucocorticoid receptor (GR) ... more The mechanism of ligand-induced (homologous) down-regulation of the glucocorticoid receptor (GR) has been studied. Dexamethasone caused a downregulation of the levels of GR mRNA and protein both in hepatoma tissue culture cells and rat liver in vivo. The decrease in the level of rat liver GR mRNA was due to a reduced transcription rate of the GR gene, as assessed by nuclear run-on transcription experiments. The half-life of GR mRNA in hepatoma tissue culture cells was determined to be approximately 4.5 h and was unaffected by dexamethasone. In addition to the transcriptional regulation of GR gene expression, a dexamethasone-dependent posttranslational modification in the rate of GR protein turnover was observed. In the absence of dexamethasone, GR protein half life was approximately 25 h whereas it decreased to approximately 11 h in the presence of hormone. Down-regulation of GR protein occurred with a 6-to 24-h delay as compared to the decline in GR mRNA. This is most likely due to the differences in half-lives of GR mRNA and protein, respectively. Our results suggest that autoregulation of GR by its cognate ligand is complex and occurs at both transcriptional and posttranslational levels. (Molecular Endocrinology 2: 1256-1264, 1988) * Recipient of a research fellowship from the Swedish Medical Research Council. t Research fellow of the Karolinska Institute.
Elsevier eBooks, 1981
ABSTRACT The [3H]triamcinolone acetonide-labeled glucocorticoid receptor from rat liver cytosol w... more ABSTRACT The [3H]triamcinolone acetonide-labeled glucocorticoid receptor from rat liver cytosol was purified to 85% homogeneity using sequential chromatography on phosphocellulose, DNA-cellulose twice, and Sephadex G-200. Between the two chromatography steps on DNA-cellulose, the receptor was heat activated. The receptor was affinity eluted from the second DNA-cellulose column with pyridoxal 5′-phosphate. After chromatography on the second DNA-cellulose column, the steroid-receptor complex had a Stokes radius of 6.0 nm and a sedimentation coefficient of 3.4 S in 0.15 M KC1. In the absence of KC1, the sedimentation coefficient was 3.6 S. An immunoglobulin (IgG) fraction from serum of a rabbit immunized with a highly purified preparation of glucocorticoid receptor contained specific antibodies to the receptor. This was shown following incubation of [3H]triamcinolone acetonice (TA)-receptor complex with the IgG fraction by I adsorption of the [3H]TA-glucocorticoid receptor-antibody complex to protein A linked to Sepharose II an increased sedimentation rate of the [3H]TA-receptor-antibody complex compared to that of the [3H]TA-receptor complex, and III an increased molecular size of the [3H]TA-receptor-antibody complex when compared to that of the [3H]TA-receptor complex as judged from gel filtration. The antibodies cross-reacted with the glucocorticoid receptor from various rat tissues (liver, thymus and hippocampus) as well as with the glucocorticoid receptor from human normal lymphocytes, chronic lymphatic leukemia cells and human hippocampus. Binding of the antibodies was not seen to the androgen, estrogen or progestin receptors in rat or to rat serum transcortin. With an indirect competitive ELISA (enzyme linked immunosorbent assay) combined with various separation techniques, based on different physico-chemical principles, it was shown that the glucocorticoid receptor was the only detectable antibody binding protein from rat liver cytosol using this assay system. Preliminary results from immunofluorescence studies on the localization of the glucocorticoid receptor in rat hypothalamus are also presented.
Journal of Biological Chemistry, Apr 1, 1984
The activated glucocorticoid receptor (GR) from rat liver cytosol was purified by sequential chro... more The activated glucocorticoid receptor (GR) from rat liver cytosol was purified by sequential chromatography on DNA-cellulose and DEAE-Sepharose. Analysis by sodium dodecyl sulfate-gel electrophoresis demonstrated a main band with M, = 94,000 (94K band). Two minor bands with M, = 79,000 (79K band) and 72,000 (72K band) were also seen in this preparation. Photoaffinity labeling showed that the hormone is bound to the 94K and 79K components but not to the 72K component. Immunoblotting using antibodies raised against the 94K protein demonstrated crossreactivity between the 94K and 79K components but not with the 72K species. The 72K species could be partially separated from the 94K and 79K components by density gradient centrifugation. Limited proteolysis of the purified GR with trypsin or a-chymotrypsin led to degradation of the 94K and 79K components and appearance of a 39K fragment which still retained the hormone and could be bound to DNA-cellulose. The 72K component was not affected by digestion with trypsin or a-chymotrypsin. However, chromatography on DNA-cellulose of the a-chymotrypsin-treated GR resulted in elution of the 72K component in the flow-through of the column while the 39K fragment was retained on the column and eluted with 0.18 M NaCl. In the control experiment where no a-chymotrypsin treatment was performed, the 72K component could not be detected in the flow-through fraction but was eluted together with the 94K and 79K components at 0.18 M NaCl. These results suggest that the 72K protein might be bound to the 94K and/or 79K component. The 39K fragment did not bind antibodies raised against the 94K protein. The 39K fragment was further degraded by trypsin but not by a-chymotrypsin to a 27K and a 25K fragment while both still retained the ligand. These data obtained with limited proteolysis of the purified GR are in agreement with previous findings on proteolysis of the GR in crude cytosol (
Splenic cells from one BALB/c mouse and one C57/BL mouse, immunized with purified rat liver gluco... more Splenic cells from one BALB/c mouse and one C57/BL mouse, immunized with purified rat liver gluco- corticoid receptor (GR), were fused with the mouse myeloma cell line Sp 2/0-Ag 14. Screening for production of anti-GR- antibodies by the hybridomas was carried out with an enzyme- linked immunosorbent assay, using partially purified rat liver GR as antigen. Further screening was by a second-antibody immunoprecipitation assay using (3H)triamcinolone aceto- nide-GR complex from rat liver cytosol as tracer. Hybrid- omas from 10 different microplate wells, positive in both as- says, were successfully cloned by the limiting dilution method to monoclonality. The different origins of the monoclonal anti- bodies were confirmed by their various isoelectric points when analyzed by isoelectric focusing. Four of the monoclonal hy- bridoma cell lines secreted IgM antibodies; two, IgGl; three, IgG2a; and one, IgG2b. The GR-antibody complex was iden- tified in glycerol density gradients by a shift of the 4S GR to an 8.5S or 19S GR-antibody complex when incubated with mono- clonal IgG or IgM antibody, respectively. The 10 monoclonal antibodies recognized different determinants on the GR, all situated on that domain of the receptor that is separate from the ligand and DNA-binding domains. Also, the cross-reactiv- ity to the mouse liver GR varied among the monoclonal anti- bodies. No cross-reactivity was observed to the human lym- phocytic GR. NaDodSO4 electrophoresis of a 0.5% pure GR preparation followed by immunoblotting using one of the
European journal of respiratory diseases. Supplement, 1982
The distribution, metabolism and protein-binding of [3H] corticosterone in the rat liver was stud... more The distribution, metabolism and protein-binding of [3H] corticosterone in the rat liver was studied with respect to time and sex. The maximum recovery from the cell nuclei occurred 5 min after injection of the steroid. At this time, ten times more radioactivity was recovered from the liver cell nuclei of male animals compared to females. The recovered radioactivity in the cell nuclei was identified as mainly unmetabolised corticosterone and 5 alpha-dihydrocorticosterone. The radioactivity bound to the cytosolic glucocorticoid receptor protein also appeared to consist of unmetabolised corticosterone and 5 alpha-dihydrocorticosterone. However, 5 alpha-dihydrocorticosterone was found to have very little biological activity. The glucocorticoid receptor was found to exist in two forms with Stokes radii of 6.1 and 3.6 nm, respectively, following in vivo labelling with [3H] dexamethasone. The 6.1 nm form could be converted into the 3.6 nm form by incubation with trypsin, papain, alpha-chy...
Toxicological Sciences, 2011
Glucocorticoids (GC) are critical for normal development of the fetal brain, and alterations in t... more Glucocorticoids (GC) are critical for normal development of the fetal brain, and alterations in their levels can induce neurotoxicity with detrimental consequences. Still, there is little information available on the effects of GC on human neural stem/progenitor cells (hNPC). In the present study, we have investigated the effects of the synthetic GC dexamethasone (Dex) on hNPC grown as neurospheres, with special focus on their proliferation and differentiation capacity and the underlying molecular mechanisms. Immunocytochemical stainings showed that Dex markedly decreases proliferation and neuronal differentiation while promoting glia cell formation. Analysis of pathway-specific genes revealed that Dex induces an upregulation of the Wnt-signaling antagonist DKK1. Moreover, Dex-or DKK1-treated hNPCs showed reduced transcriptional levels of the two canonical Wnt target genes cyclin D1 and inhibitor of DNA binding 2 (ID2). Chromatin immunoprecipitation showed that Dex, via the glucocorticoid receptor, interacts with the DKK1 promotor. Treatment of hNPC with recombinant DKK1 or neutralizing antibodies indicated that DKK1 has a critical role in the Dexinduced inhibition of proliferation and neuronal differentiation with a concomitant increase in glial cells. Taken together, our findings show that GC reduce proliferation and interfere with differentiation of hNPCs via the canonical Wnt-signaling pathway.
Neuroscience Letters, 1985
By means of the indirect immunoperoxidase technique the corticotrophin releasing factor (CRF) and... more By means of the indirect immunoperoxidase technique the corticotrophin releasing factor (CRF) and glucocorticoid receptor (OR) immunoreactive nerve cell bodies and the phenylethanolamine-Nmethyltransferase (PNMT) immunoreactive nerve terminals in the paraventricular hypothalamic nucleus of the rat have been mapped out in adjacent vibratome sections (30 Jtm thick). By means of marphometrical analysis using a semiautomatic image analyser, it was possible to obtain density maps of CRF. OR and PNMT immunoreactive structures within the paraventricular hypothalamic nucleus. The statistical analysis by the use of correlation coefficients gives evidence that the PNMT immunoreactive nerve terminals innervate the majority of the CRF immunoreactive nerve cell bodies and that OR are located in the majority of the CRF immunoreactive neurons.
Neuroscience, 1994
By means of a monoclonal mouse immunoglobulin G2a antibody against the rat liver glucocorticoid r... more By means of a monoclonal mouse immunoglobulin G2a antibody against the rat liver glucocorticoid receptor and the indirect immunoperoxidase technique, the distribution of glucocorticoid receptors in neuronal and glial cell populations was mapped in the central nervous system of the male rat. The mapping was complemented by computer-assisted morphometric and microdensitometric evaluation of glucocorticoid receptor immunoreactivity in many brain regions. The quantitative analysis I VI 4 2.8.9 3n ac aca A&C AcbSh aci AD AHA Ai AOD AOL AOM AOV AP ar Arc AV BL BSTD BSTL BSTM Cl, c2, c3 CA1-4 CAU CC Ce Cg CG Cl CL CM ZPu CPU dm CPU vi cu DEn
Nature, 1984
The effects of steroid hormones are mediated by intracellular hormone-specific receptor proteins;... more The effects of steroid hormones are mediated by intracellular hormone-specific receptor proteins; the interaction between the hormone and its receptor increases the affinity of the receptor for nuclear binding sites, thereby modulating the expression of specific genes. The glucocorticoid receptor is a soluble protein of relative molecular mass (Mr) 94,000 (94K), present at a low relative abundance (less than or equal to 0.01%); it has been purified to near-homogeneity, and specific antisera and monoclonal antibodies have been produced. Purified glucocorticoid receptor binds in vitro with high affinity to defined regions of DNA near regulated promoters, and sequences essential for these interactions are functional in vivo as hormone-dependent transcriptional enhancer elements. We have now cloned complementary DNA (cDNA) for the rat liver glucocorticoid receptor and we describe here a 2.6-kilobase (kb) receptor cDNA isolated following polysome immuno-enrichment of receptor messenger RNA with glucocorticoid receptor-specific antibodies. The receptor appears to be encoded by a single-copy gene which specifies a approximately 6-kb transcript in rat and mouse cells; this mRNA is altered quantitatively and qualitatively in several mutant cell lines with specific defects in receptor function.
Molecular Endocrinology, 1995
Glucocorticoids are efficient antiinflammatory agents, and their effects include transcriptional ... more Glucocorticoids are efficient antiinflammatory agents, and their effects include transcriptional repression of several cytokines and adhesion molecules. Whereas glucocorticoids down-regulate the expression of genes relevant during inflammation, nuclear factor (NF)-&/Rel proteins function as important positive regulators of these genes. The expression of intercellular adhesion molecule-l (ICAM-I), which plays an essential role in recruitment and migration of leukocytes to sites of inflammation, is also down-regulated by glucocorticoids. We found that a functional NF-KB site in the ICAM-promoter, which can be activated by either 12-0-tetradecanoylphorbol-13-acetate or tumor necrosis factor-a (TNFru), is also the target for glucocorticoids. In this report we present evidence that the ligand-activated glucocorticoid receptor (GR) is able to repress RelA-mediated activation of the ICAM-NF-KB site. Conversely, transcriptional activation by GR via a glucocotticoid response element is specifically repressed by RelA, but not by other NF-KB/Rel family members. Mutational analysis of GR demonstrates that the DNA binding domain and the ligand binding domain are required for the functional repression of NF-KB activation. Despite the importance of the DNA binding domain, we found that the transcriptional repression of NF-KB, mediated by GR, is not caused by binding om-8809/95/$3.00/O Molecular Endocrinology CopyrIght 0 1995 by The Endocrine Soclety of GR to the ICAM-I NF-KB element, but by a physical interaction between the GR and RelA protein. The repressive effect of GR on NF-KB-mediated activation was not shared by other steroid/thyroid receptors. Only the progesterone receptor, which belongs to the same subfamily as GR and which possesses high homology with GR, was able to repress NF-KB-mediated transcription. These studies highlight a possible molecular mechanism that can explain the antiinflammatory effects of glucocorticoid treatment during inflammation.
Journal of Biological Chemistry, 1998
PubMed, 1984
Limited proteolysis of the glucocorticoid receptor has proven to be a valuable tool for a functio... more Limited proteolysis of the glucocorticoid receptor has proven to be a valuable tool for a functional analysis of the receptor protein. With the help of these analyses, it has been possible to describe three functional domains of the receptor protein. The native glucocorticoid-receptor complex contains a steroid-binding domain (A), a DNA-binding domain (B) and an immunoactive domain (C). This form of the glucocorticoid receptor has a Stokes radius of 6.1 nm and a molecular weight of 94 K when purified. Two steroid-binding proteolytic receptor fragments can be found. The larger one has a Stokes radius of 3.3 - 3.6 nm and a molecular weight of 39 K and contains both the steroid- and DNA-binding sites (A + B). The smaller steroid-binding receptor fragment, with a Stokes radius of 1.9 nm and a molecular weight of 27 K, contains only the steroid-binding domain (A). Analysis of the proteolytic fragments of the glucocorticoid receptor using the specific anti-receptor antibodies revealed the occurrence of a fragment with Stokes radius 2.6 nm following limited proteolysis of the receptor by alpha-chymotrypsin. This fragment contains neither the steroid-binding nor the DNA-binding domains but consists only of the immunoactive domain (C). Further proteolysis of this fragment results in an even smaller form with Stokes radius 1.4 nm. The apparent identity of the larger of the two proteolytic forms of the glucocorticoid receptor (the 3.3 - 3.6 nm form) with the receptor isolated from certain corticosteroid-resistant cells, together with the lack of the immunoreactive domain in these cells appears to indicate an important function of this domain with regard to the biological activity of the receptor.
PubMed, 1990
... 1990;322:65-80. Structure, function and regulation of the glucocorticoid receptor. Gustafsson... more ... 1990;322:65-80. Structure, function and regulation of the glucocorticoid receptor. Gustafsson JA, Carlstedt-Duke J, Strömstedt PE, Wikström AC, Denis M, Okret S, Dong Y. Department of Medical Nutrition, Karolinska Institute, Huddinge University Hospital F69, Sweden. ...
PubMed, Jul 1, 1983
Glucocorticoid-resistant (CR), in contrast to glucocorticoid-sensitive (CS), mouse lymphoma P1798... more Glucocorticoid-resistant (CR), in contrast to glucocorticoid-sensitive (CS), mouse lymphoma P1798 was shown to lack antiglucocorticoid receptor immunoactivity. Antibodies raised against the purified rat liver glucocorticoid receptor (GR) cross-reacted with the GR from CS, but not with the GR from CR, P1798 lymphoma. Using highly specific antisera against the GR in an indirect competitive enzyme-linked immunosorbent assay, it was demonstrated that alpha-chymotrypsin digestion of the GR from CS P1798 lymphoma caused a separation of a "resistant-like" nonimmunogenic steroid and DNA-binding domain (Stokes' radius, 3.3 nm) from an immunoactive domain (Stokes' radius, 2.6 nm). In contrast to CS P1798 lymphoma, neither before nor after alpha-chymotrypsin digestion, immunoactivity could be found in the cytosol from CR P1798 lymphoma. This was assayed after chromatography on DNA-cellulose or gel filtration on Agarose A (0.5 m). These results suggest that the domain of the CS GR containing the immunoactive determinant(s), normally removed by limited proteolysis by alpha-chymotrypsin, appears to be missing in CR P1798 lymphoma cytosol. It seems that this domain plays an important role in the mechanism of action of glucocorticoids. This might suggest that a mutation has occurred affecting the genome resulting in defective transcription of the receptor gene(s) in CR P1798 lymphoma.
Endocrinology, May 1, 1992
Monoclonal antibodies directed against four different polypeptide epitopes on the Mr approximatel... more Monoclonal antibodies directed against four different polypeptide epitopes on the Mr approximately 94,000 steroid-binding subunit of the rat liver cytosolic glucocorticoid receptor (GcR) were used to probe Western blots of epididymal spermatozoa from rats and mice. Two sperm polypeptides with apparent molecular weights of 94,000 (indistinguishable in size from the liver GcR subunit) and 150,000 reacted with these antibodies. Other polypeptides that are present in a wide variety of somatic cells [lamin-A, -B, and -C; topoisomerase-I; poly(ADP-ribose) polymerase; the 62-kilodalton internal nuclear matrix protein; the nucleolar protein B23; and histone H1] could not be detected in these preparations of spermatozoa, thus appearing to rule out contamination by somatic cells. Rat and mouse pachytene spermatocytes and round spermatids contained much lower amounts of the Mr approximately 94,000 and 150,000 polypeptides. These results suggested that the steroid-binding subunit of the GcR might be accumulated late in spermatogenesis. Consistent with this view, a 6-kilobase mRNA (identical in size to a mRNA detected in mouse somatic cell lines) was detected when Northern blots of mouse round spermatid RNA were probed with a cDNA to the steroid-binding GcR subunit. Although the results described above suggest the presence of GcR in rodent sperm, high affinity binding of glucocorticoids to epididymal sperm could not be detected in a whole cell binding assay. Further analysis revealed that the Mr approximately 90,000 heat shock protein (hsp90), a component reportedly required for high affinity ligand binding to the GcR, was present in early germ cells, but absent from rodent epididymal sperm. These results suggest that the Mr approximately 94,000 steroid-binding subunit of the GcR and an immunologically related Mr approximately 150,000 polypeptide are specifically accumulated during the later stages of rodent spermatogenesis, but are not assembled into receptor complexes capable of binding steroid. In addition, these results support the view that hsp90 is required for high affinity binding of glucocorticoids to the Mr approximately 94,000 GcR subunit in intact cells.
Biochimica et biophysica acta. Molecular cell research, Mar 1, 2009
Glucocorticoid (GC) effects are mediated via the GC-receptor (GR), which either stimulates or rep... more Glucocorticoid (GC) effects are mediated via the GC-receptor (GR), which either stimulates or represses gene expression. Repression of target genes often involves negative cross-talk between the GR and other transcription factors e.g. NF-kappaB, important for gene activation. Using HEK293 cells we here describe that repression of NF-kappaB requires functions of the GR that are dependent on the signaling pathways employed to activate NF-kappaB. While a GR mutant was able to repress NF-kappaB activity following activation by TNFalpha, it did not so following activation by the phorbol ester TPA. In these cells, TPA stimulation but not TNFalpha, activated extracellular signal-regulated kinase (ERK). We demonstrated that the ability of the dexamethasone activated GR mutant to repress TPA-induced NF-kappaB activity was restored in conjunction with ERK1/2 inhibition. Previous reports have shown GC-mediated inhibition of ERK1/2 phosphorylation to involve GC induction of MAPK phosphatase-1 (MKP-1). Here, we demonstrated that the GRR488Q mutant was incapable of inducing gene expression of endogenous MKP-1 following dexamethasone treatment, in contrast to the GRwt. However, TPA treatment alone resulted in much stronger MKP-1 expression in both GRwt and GRR488Q containing cells than that of dexamethasone suggesting that the inability of GRR488Q to inhibit TPA-induced NF-kappaB activity did not involve a lack of MKP-1 expression. In line with this, RNAi targeted towards MKP-1 did not abolish or inhibit the ability of the GRwt to repress NF-kappaB activity. Importantly, we observed no difference in activated ERK1/2 (phospho-ERK1/2) expression over time between GRwt and GRR488Q containing cells following co-treatment with TPA and dexamethasone. Based on these results we suggest that GRwt does not directly regulate ERK1/2 but rather alters ERK1/2-mediated effects allowing it to repress NF-kappaB activity, a capacity lacked by the GRR488Q mutant.
Journal of Biological Chemistry, Sep 1, 1986
The nuclear matrix is a putative skeletal structure which has been implicated in many nuclear fun... more The nuclear matrix is a putative skeletal structure which has been implicated in many nuclear functions. To assess a possible role of the nuclear matrix in glucocorticoid action, purified rat liver nuclei containing glucocorticoid-receptor complexes were treated with DNase I +/- RNase A followed by 1.6 M NaCl, thus yielding salt-extractable and salt-resistant (nuclear matrix) fractions. The subnuclear distribution of hormone-receptor complexes was determined by following the fate of unmetabolized radiolabel after injection of labeled triamcinolone acetonide into adrenalectomized animals and subjecting various subfractions to immunoblotting using a monoclonal antibody which recognizes the glucocorticoid receptor. Both techniques indicated that 50-70% of the total nuclear hormone-receptor complexes were recovered in the nuclear matrix fraction. Previous results (Kaufmann, S. H., and Shaper, J. H. (1984) Exp. Cell Res. 155, 477-495) suggest that a variety of nuclear polypeptides become nuclease- and salt-resistant as a result of the formation of intermolecular disulfide bonds. The following evidence suggests that disulfide bonds mediate the association between the glucocorticoid receptor and the nuclear matrix. When nuclei were isolated in the absence of sulfhydryl-blocking and -cross-linking reagents, sodium dodecyl sulfate-polyacrylamide gel electrophoresis under nonreducing conditions revealed that the receptor was present as a high molecular weight disulfide-cross-linked complex. When nuclei were isolated in the presence of the irreversible sulfhydryl-blocking reagent iodoacetamide, the disulfide bonds which cross-linked the receptor into high molecular weight complexes were absent; and 85-100% of the hormone-receptor complexes were salt-extractable. When nuclei (isolated in the absence of iodoacetamide) were treated with the sulfhydryl-cross-linking reagent sodium tetrathionate, greater than 95% of the nuclear hormone-receptor complexes became resistant to extraction with nucleases and 1.6 M NaCl. The implications of these results for other matrix-associated nuclear functions are discussed.
Endocrine Reviews, May 1, 1987
THE INTRACELLULAR receptor proteins for steroid hormones are a group of transcriptional regulator... more THE INTRACELLULAR receptor proteins for steroid hormones are a group of transcriptional regulatory proteins with several common features, acting by direct interaction with DNA. The protein must first be activated by the binding of the appropriate class of steroid. The ...
Nature, Dec 1, 1984
The effects of steroid hormones are mediated by intracellular hormone-specific receptor proteins;... more The effects of steroid hormones are mediated by intracellular hormone-specific receptor proteins; the interaction between the hormone and its receptor increases the affinity of the receptor for nuclear binding sites, thereby modulating the expression of specific genes. The glucocorticoid receptor is a soluble protein of relative molecular mass (Mr) 94,000 (94K), present at a low relative abundance (less than or equal to 0.01%); it has been purified to near-homogeneity, and specific antisera and monoclonal antibodies have been produced. Purified glucocorticoid receptor binds in vitro with high affinity to defined regions of DNA near regulated promoters, and sequences essential for these interactions are functional in vivo as hormone-dependent transcriptional enhancer elements. We have now cloned complementary DNA (cDNA) for the rat liver glucocorticoid receptor and we describe here a 2.6-kilobase (kb) receptor cDNA isolated following polysome immuno-enrichment of receptor messenger RNA with glucocorticoid receptor-specific antibodies. The receptor appears to be encoded by a single-copy gene which specifies a approximately 6-kb transcript in rat and mouse cells; this mRNA is altered quantitatively and qualitatively in several mutant cell lines with specific defects in receptor function.
Molecular Endocrinology, Dec 1, 1988
The mechanism of ligand-induced (homologous) down-regulation of the glucocorticoid receptor (GR) ... more The mechanism of ligand-induced (homologous) down-regulation of the glucocorticoid receptor (GR) has been studied. Dexamethasone caused a downregulation of the levels of GR mRNA and protein both in hepatoma tissue culture cells and rat liver in vivo. The decrease in the level of rat liver GR mRNA was due to a reduced transcription rate of the GR gene, as assessed by nuclear run-on transcription experiments. The half-life of GR mRNA in hepatoma tissue culture cells was determined to be approximately 4.5 h and was unaffected by dexamethasone. In addition to the transcriptional regulation of GR gene expression, a dexamethasone-dependent posttranslational modification in the rate of GR protein turnover was observed. In the absence of dexamethasone, GR protein half life was approximately 25 h whereas it decreased to approximately 11 h in the presence of hormone. Down-regulation of GR protein occurred with a 6-to 24-h delay as compared to the decline in GR mRNA. This is most likely due to the differences in half-lives of GR mRNA and protein, respectively. Our results suggest that autoregulation of GR by its cognate ligand is complex and occurs at both transcriptional and posttranslational levels. (Molecular Endocrinology 2: 1256-1264, 1988) * Recipient of a research fellowship from the Swedish Medical Research Council. t Research fellow of the Karolinska Institute.
Elsevier eBooks, 1981
ABSTRACT The [3H]triamcinolone acetonide-labeled glucocorticoid receptor from rat liver cytosol w... more ABSTRACT The [3H]triamcinolone acetonide-labeled glucocorticoid receptor from rat liver cytosol was purified to 85% homogeneity using sequential chromatography on phosphocellulose, DNA-cellulose twice, and Sephadex G-200. Between the two chromatography steps on DNA-cellulose, the receptor was heat activated. The receptor was affinity eluted from the second DNA-cellulose column with pyridoxal 5′-phosphate. After chromatography on the second DNA-cellulose column, the steroid-receptor complex had a Stokes radius of 6.0 nm and a sedimentation coefficient of 3.4 S in 0.15 M KC1. In the absence of KC1, the sedimentation coefficient was 3.6 S. An immunoglobulin (IgG) fraction from serum of a rabbit immunized with a highly purified preparation of glucocorticoid receptor contained specific antibodies to the receptor. This was shown following incubation of [3H]triamcinolone acetonice (TA)-receptor complex with the IgG fraction by I adsorption of the [3H]TA-glucocorticoid receptor-antibody complex to protein A linked to Sepharose II an increased sedimentation rate of the [3H]TA-receptor-antibody complex compared to that of the [3H]TA-receptor complex, and III an increased molecular size of the [3H]TA-receptor-antibody complex when compared to that of the [3H]TA-receptor complex as judged from gel filtration. The antibodies cross-reacted with the glucocorticoid receptor from various rat tissues (liver, thymus and hippocampus) as well as with the glucocorticoid receptor from human normal lymphocytes, chronic lymphatic leukemia cells and human hippocampus. Binding of the antibodies was not seen to the androgen, estrogen or progestin receptors in rat or to rat serum transcortin. With an indirect competitive ELISA (enzyme linked immunosorbent assay) combined with various separation techniques, based on different physico-chemical principles, it was shown that the glucocorticoid receptor was the only detectable antibody binding protein from rat liver cytosol using this assay system. Preliminary results from immunofluorescence studies on the localization of the glucocorticoid receptor in rat hypothalamus are also presented.
Journal of Biological Chemistry, Apr 1, 1984
The activated glucocorticoid receptor (GR) from rat liver cytosol was purified by sequential chro... more The activated glucocorticoid receptor (GR) from rat liver cytosol was purified by sequential chromatography on DNA-cellulose and DEAE-Sepharose. Analysis by sodium dodecyl sulfate-gel electrophoresis demonstrated a main band with M, = 94,000 (94K band). Two minor bands with M, = 79,000 (79K band) and 72,000 (72K band) were also seen in this preparation. Photoaffinity labeling showed that the hormone is bound to the 94K and 79K components but not to the 72K component. Immunoblotting using antibodies raised against the 94K protein demonstrated crossreactivity between the 94K and 79K components but not with the 72K species. The 72K species could be partially separated from the 94K and 79K components by density gradient centrifugation. Limited proteolysis of the purified GR with trypsin or a-chymotrypsin led to degradation of the 94K and 79K components and appearance of a 39K fragment which still retained the hormone and could be bound to DNA-cellulose. The 72K component was not affected by digestion with trypsin or a-chymotrypsin. However, chromatography on DNA-cellulose of the a-chymotrypsin-treated GR resulted in elution of the 72K component in the flow-through of the column while the 39K fragment was retained on the column and eluted with 0.18 M NaCl. In the control experiment where no a-chymotrypsin treatment was performed, the 72K component could not be detected in the flow-through fraction but was eluted together with the 94K and 79K components at 0.18 M NaCl. These results suggest that the 72K protein might be bound to the 94K and/or 79K component. The 39K fragment did not bind antibodies raised against the 94K protein. The 39K fragment was further degraded by trypsin but not by a-chymotrypsin to a 27K and a 25K fragment while both still retained the ligand. These data obtained with limited proteolysis of the purified GR are in agreement with previous findings on proteolysis of the GR in crude cytosol (
Splenic cells from one BALB/c mouse and one C57/BL mouse, immunized with purified rat liver gluco... more Splenic cells from one BALB/c mouse and one C57/BL mouse, immunized with purified rat liver gluco- corticoid receptor (GR), were fused with the mouse myeloma cell line Sp 2/0-Ag 14. Screening for production of anti-GR- antibodies by the hybridomas was carried out with an enzyme- linked immunosorbent assay, using partially purified rat liver GR as antigen. Further screening was by a second-antibody immunoprecipitation assay using (3H)triamcinolone aceto- nide-GR complex from rat liver cytosol as tracer. Hybrid- omas from 10 different microplate wells, positive in both as- says, were successfully cloned by the limiting dilution method to monoclonality. The different origins of the monoclonal anti- bodies were confirmed by their various isoelectric points when analyzed by isoelectric focusing. Four of the monoclonal hy- bridoma cell lines secreted IgM antibodies; two, IgGl; three, IgG2a; and one, IgG2b. The GR-antibody complex was iden- tified in glycerol density gradients by a shift of the 4S GR to an 8.5S or 19S GR-antibody complex when incubated with mono- clonal IgG or IgM antibody, respectively. The 10 monoclonal antibodies recognized different determinants on the GR, all situated on that domain of the receptor that is separate from the ligand and DNA-binding domains. Also, the cross-reactiv- ity to the mouse liver GR varied among the monoclonal anti- bodies. No cross-reactivity was observed to the human lym- phocytic GR. NaDodSO4 electrophoresis of a 0.5% pure GR preparation followed by immunoblotting using one of the
European journal of respiratory diseases. Supplement, 1982
The distribution, metabolism and protein-binding of [3H] corticosterone in the rat liver was stud... more The distribution, metabolism and protein-binding of [3H] corticosterone in the rat liver was studied with respect to time and sex. The maximum recovery from the cell nuclei occurred 5 min after injection of the steroid. At this time, ten times more radioactivity was recovered from the liver cell nuclei of male animals compared to females. The recovered radioactivity in the cell nuclei was identified as mainly unmetabolised corticosterone and 5 alpha-dihydrocorticosterone. The radioactivity bound to the cytosolic glucocorticoid receptor protein also appeared to consist of unmetabolised corticosterone and 5 alpha-dihydrocorticosterone. However, 5 alpha-dihydrocorticosterone was found to have very little biological activity. The glucocorticoid receptor was found to exist in two forms with Stokes radii of 6.1 and 3.6 nm, respectively, following in vivo labelling with [3H] dexamethasone. The 6.1 nm form could be converted into the 3.6 nm form by incubation with trypsin, papain, alpha-chy...
Toxicological Sciences, 2011
Glucocorticoids (GC) are critical for normal development of the fetal brain, and alterations in t... more Glucocorticoids (GC) are critical for normal development of the fetal brain, and alterations in their levels can induce neurotoxicity with detrimental consequences. Still, there is little information available on the effects of GC on human neural stem/progenitor cells (hNPC). In the present study, we have investigated the effects of the synthetic GC dexamethasone (Dex) on hNPC grown as neurospheres, with special focus on their proliferation and differentiation capacity and the underlying molecular mechanisms. Immunocytochemical stainings showed that Dex markedly decreases proliferation and neuronal differentiation while promoting glia cell formation. Analysis of pathway-specific genes revealed that Dex induces an upregulation of the Wnt-signaling antagonist DKK1. Moreover, Dex-or DKK1-treated hNPCs showed reduced transcriptional levels of the two canonical Wnt target genes cyclin D1 and inhibitor of DNA binding 2 (ID2). Chromatin immunoprecipitation showed that Dex, via the glucocorticoid receptor, interacts with the DKK1 promotor. Treatment of hNPC with recombinant DKK1 or neutralizing antibodies indicated that DKK1 has a critical role in the Dexinduced inhibition of proliferation and neuronal differentiation with a concomitant increase in glial cells. Taken together, our findings show that GC reduce proliferation and interfere with differentiation of hNPCs via the canonical Wnt-signaling pathway.
Neuroscience Letters, 1985
By means of the indirect immunoperoxidase technique the corticotrophin releasing factor (CRF) and... more By means of the indirect immunoperoxidase technique the corticotrophin releasing factor (CRF) and glucocorticoid receptor (OR) immunoreactive nerve cell bodies and the phenylethanolamine-Nmethyltransferase (PNMT) immunoreactive nerve terminals in the paraventricular hypothalamic nucleus of the rat have been mapped out in adjacent vibratome sections (30 Jtm thick). By means of marphometrical analysis using a semiautomatic image analyser, it was possible to obtain density maps of CRF. OR and PNMT immunoreactive structures within the paraventricular hypothalamic nucleus. The statistical analysis by the use of correlation coefficients gives evidence that the PNMT immunoreactive nerve terminals innervate the majority of the CRF immunoreactive nerve cell bodies and that OR are located in the majority of the CRF immunoreactive neurons.
Neuroscience, 1994
By means of a monoclonal mouse immunoglobulin G2a antibody against the rat liver glucocorticoid r... more By means of a monoclonal mouse immunoglobulin G2a antibody against the rat liver glucocorticoid receptor and the indirect immunoperoxidase technique, the distribution of glucocorticoid receptors in neuronal and glial cell populations was mapped in the central nervous system of the male rat. The mapping was complemented by computer-assisted morphometric and microdensitometric evaluation of glucocorticoid receptor immunoreactivity in many brain regions. The quantitative analysis I VI 4 2.8.9 3n ac aca A&C AcbSh aci AD AHA Ai AOD AOL AOM AOV AP ar Arc AV BL BSTD BSTL BSTM Cl, c2, c3 CA1-4 CAU CC Ce Cg CG Cl CL CM ZPu CPU dm CPU vi cu DEn
Nature, 1984
The effects of steroid hormones are mediated by intracellular hormone-specific receptor proteins;... more The effects of steroid hormones are mediated by intracellular hormone-specific receptor proteins; the interaction between the hormone and its receptor increases the affinity of the receptor for nuclear binding sites, thereby modulating the expression of specific genes. The glucocorticoid receptor is a soluble protein of relative molecular mass (Mr) 94,000 (94K), present at a low relative abundance (less than or equal to 0.01%); it has been purified to near-homogeneity, and specific antisera and monoclonal antibodies have been produced. Purified glucocorticoid receptor binds in vitro with high affinity to defined regions of DNA near regulated promoters, and sequences essential for these interactions are functional in vivo as hormone-dependent transcriptional enhancer elements. We have now cloned complementary DNA (cDNA) for the rat liver glucocorticoid receptor and we describe here a 2.6-kilobase (kb) receptor cDNA isolated following polysome immuno-enrichment of receptor messenger RNA with glucocorticoid receptor-specific antibodies. The receptor appears to be encoded by a single-copy gene which specifies a approximately 6-kb transcript in rat and mouse cells; this mRNA is altered quantitatively and qualitatively in several mutant cell lines with specific defects in receptor function.
Molecular Endocrinology, 1995
Glucocorticoids are efficient antiinflammatory agents, and their effects include transcriptional ... more Glucocorticoids are efficient antiinflammatory agents, and their effects include transcriptional repression of several cytokines and adhesion molecules. Whereas glucocorticoids down-regulate the expression of genes relevant during inflammation, nuclear factor (NF)-&/Rel proteins function as important positive regulators of these genes. The expression of intercellular adhesion molecule-l (ICAM-I), which plays an essential role in recruitment and migration of leukocytes to sites of inflammation, is also down-regulated by glucocorticoids. We found that a functional NF-KB site in the ICAM-promoter, which can be activated by either 12-0-tetradecanoylphorbol-13-acetate or tumor necrosis factor-a (TNFru), is also the target for glucocorticoids. In this report we present evidence that the ligand-activated glucocorticoid receptor (GR) is able to repress RelA-mediated activation of the ICAM-NF-KB site. Conversely, transcriptional activation by GR via a glucocotticoid response element is specifically repressed by RelA, but not by other NF-KB/Rel family members. Mutational analysis of GR demonstrates that the DNA binding domain and the ligand binding domain are required for the functional repression of NF-KB activation. Despite the importance of the DNA binding domain, we found that the transcriptional repression of NF-KB, mediated by GR, is not caused by binding om-8809/95/$3.00/O Molecular Endocrinology CopyrIght 0 1995 by The Endocrine Soclety of GR to the ICAM-I NF-KB element, but by a physical interaction between the GR and RelA protein. The repressive effect of GR on NF-KB-mediated activation was not shared by other steroid/thyroid receptors. Only the progesterone receptor, which belongs to the same subfamily as GR and which possesses high homology with GR, was able to repress NF-KB-mediated transcription. These studies highlight a possible molecular mechanism that can explain the antiinflammatory effects of glucocorticoid treatment during inflammation.
Journal of Biological Chemistry, 1998