scholarly journals Structural Determinants of Constitutive Androstane Receptor Required for Its Glucocorticoid Receptor Interacting Protein-1-mediated Nuclear Accumulation

2004 ◽  
Vol 280 (8) ◽  
pp. 7285-7293 ◽  
Author(s):  
Jun Xia ◽  
Byron Kemper
Keyword(s):  
Glucocorticoid Receptor ◽  
Constitutive Androstane Receptor ◽  
Nuclear Accumulation ◽  
Structural Determinants ◽  
Interacting Protein

scholarly journals Glucocorticoid Receptor Phosphorylation Differentially Affects Target Gene Expression

2008 ◽  
Vol 22 (8) ◽  
pp. 1754-1766 ◽  
Author(s):  
Weiwei Chen ◽  
Thoa Dang ◽  
Raymond D. Blind ◽  
Zhen Wang ◽  
Claudio N. Cavasotto ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Transcriptional Activation ◽  
Leucine Zipper ◽  
Target Genes ◽  
Divalent Cations ◽  
Phosphorylation Site ◽  
Transcriptional Response ◽  
Receptor Occupancy ◽  
Wild Type ◽  
Interacting Protein

Abstract The glucocorticoid receptor (GR) is phosphorylated at multiple sites within its N terminus (S203, S211, S226), yet the role of phosphorylation in receptor function is not understood. Using a range of agonists and GR phosphorylation site-specific antibodies, we demonstrated that GR transcriptional activation is greatest when the relative phosphorylation of S211 exceeds that of S226. Consistent with this finding, a replacement of S226 with an alanine enhances GR transcriptional response. Using a battery of compounds that perturb different signaling pathways, we found that BAPTA-AM, a chelator of intracellular divalent cations, and curcumin, a natural product with antiinflammatory properties, reduced hormone-dependent phosphorylation at S211. This change in GR phosphorylation was associated with its decreased nuclear retention and transcriptional activation. Molecular modeling suggests that GR S211 phosphorylation promotes a conformational change, which exposes a novel surface potentially facilitating cofactor interaction. Indeed, S211 phosphorylation enhances GR interaction with MED14 (vitamin D receptor interacting protein 150). Interestingly, in U2OS cells expressing a nonphosphorylated GR mutant S211A, the expression of IGF-binding protein 1 and interferon regulatory factor 8, both MED14-dependent GR target genes, was reduced relative to cells expressing wild-type receptor across a broad range of hormone concentrations. In contrast, the induction of glucocorticoid-induced leucine zipper, a MED14-independent GR target, was similar in S211A- and wild-type GR-expressing cells at high hormone levels, but was reduced in S211A cells at low hormone concentrations, suggesting a link between GR phosphorylation, MED14 involvement, and receptor occupancy. Phosphorylation also affected the magnitude of repression by GR in a gene-selective manner. Thus, GR phosphorylation at S211 and S226 determines GR transcriptional response by modifying cofactor interaction. Furthermore, the effect of GR S211 phosphorylation is gene specific and, in some cases, dependent upon the amount of activated receptor.

Specific inhibition of transcriptional activity of the constitutive androstane receptor (CAR) by the splicing factor SF3a3

2008 ◽  
Vol 389 (10) ◽  
Author(s):  
Hye Jin Yun ◽  
Jungsun Kwon ◽  
Wongi Seol
Keyword(s):  
Transcriptional Activity ◽  
Constitutive Androstane Receptor ◽  
Splicing Factor ◽  
Yeast Two Hybrid ◽  
Interacting Protein ◽  
Functional Studies ◽  
Reporter Activity ◽  
Inhibitory Function ◽  
Two Hybrid ◽  
Hybrid Screening

Abstract The constitutive androstane receptor (CAR) is a member of the nuclear receptor superfamily and plays an important role in the degradation of xenobiotics in the liver. Using yeast two-hybrid screening, we identified SF3a3, a 60-kDa subunit of the splicing factor 3a complex, as a specific CAR-interacting protein. We further confirmed their interaction by both co-immunoprecipitation and GST pull-down assay. Functional studies showed that overexpression of SF3a3 inhibited the reporter activity driven by a promoter containing CAR binding sequences by up to 50%, whereas reduced expression of SF3a3 activated the same reporter activity by approximately three-fold. The inhibitory function of SF3a3 is independent of the presence of TCPOBOP, a CAR ligand. These data suggest that SF3a3 functions as a co-repressor of CAR transcriptional activity, in addition to its canonical function.

scholarly journals Structural Determinants of a Glucocorticoid Receptor Recognition Element

1990 ◽  
Vol 4 (12) ◽  
pp. 1866-1873 ◽  
Author(s):  
Steven K. Nordeen ◽  
Betty J. Suh ◽  
Blanka Kühnel ◽  
Clyde A. Hutchison
Keyword(s):  
Glucocorticoid Receptor ◽  
Structural Determinants ◽  
Recognition Element ◽  
Receptor Recognition

scholarly journals β-catenin Mutations Are Not Involved in Early-stage Hepatocarcinogenesis Induced by Protoporphyrinogen Oxidase Inhibitors in Mice

2017 ◽  
Vol 45 (4) ◽  
pp. 493-505
Author(s):  
Kazunori Kuwata ◽  
Kaoru Inoue ◽  
Ryohei Ichimura ◽  
Miwa Takahashi ◽  
Yukio Kodama ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
High Frequency ◽  
Early Stage ◽  
Constitutive Androstane Receptor ◽  
Nuclear Accumulation ◽  
Molecular Characteristics ◽  
Wild Type ◽  
Protoporphyrinogen Oxidase ◽  
Neoplastic Lesions ◽  
Molecular Profiles

We previously reported the contribution of constitutive androstane receptor (CAR) in cytotoxicity-related hepatocarcinogenesis induced by oxadiazon (OX) or acifluorfen (ACI), two pesticides categorized as protoporphyrinogen oxidase (PROTOX) inhibitors. The molecular characteristics of preneoplastic and neoplastic lesions induced by OX and ACI were immunohistochemically compared to those by phenobarbital (PB), a typical CAR activator, in wild-type (WT) and CAR knockout (CARKO) mice after diethylnitrosamine initiation. We focused on changes in β-catenin and its transcriptional product glutamine synthetase (GS). In PB-promoted foci and adenomas, nuclear accumulation of mutated β-catenin was increased with high frequency. PB treatment also increased the multiplicity and area of GS-positive foci and adenomas in WT mice. No foci and adenomas showed nuclear accumulation of β-catenin and expression of GS in CARKO mice, similar to both genotypes of mice treated with OX and ACI. Interestingly, hepatocellular carcinoma induced in ACI-treated WT mice showed nuclear accumulation of β-catenin and was positive for GS. Our results indicated that β-catenin mutations were not involved in early-stage hepatocarcinogenesis induced by PROTOX inhibitors in mice, although activation of β-catenin and CAR is important in PB-induced tumorigenesis. The significant differences in molecular profiles suggested involvements of multiple mode of actions for hepatocarcinogenesis induced by PROTOX inhibitors.

scholarly journals Analysis of two CBP (cAMP-response-element-binding protein-binding protein) interacting sites in GRIP1 (glucocorticoid-receptor-interacting protein), and their importance for the function of GRIP1

2004 ◽  
Vol 382 (1) ◽  
pp. 111-119 ◽  
Author(s):  
Shih-Ming HUANG ◽  
Yi-Shan CHENG
Keyword(s):  
Amino Acids ◽  
Glucocorticoid Receptor ◽  
Protein Binding ◽  
Hela Cells ◽  
Binding Protein ◽  
Camp Response Element Binding ◽  
Camp Response Element ◽  
Interacting Protein ◽  
Transactivation Activity ◽  
Element Binding Protein

The p160 co-activators, SRC1 (steroid receptor co-activator 1), GRIP1 (glucocorticoid-receptor-interacting protein 1) and ACTR (activator for thyroid hormone and retinoid receptors), have two ADs (activation domains), AD1 and AD2. AD1 is a binding site for the related co-activators, CBP (cAMP-response-element-binding protein-binding protein) and p300, whereas AD2 binds to another co-activator, co-activator-associated arginine methyltransferase 1 (CARM1). Here, we identified two CBP-interacting sites [amino acids 1075–1083 (site I) and 1095–1106 (site II)] in a so-called CBP-dependent transactivation domain (AD1; amino acids 1057–1109) of GRIP1. Site I was the major site for CBP-dependent AD1 transactivation activity of GRIP1 whereas, following the deletion of site II, full or partial transactivation activity was retained without the recruitment of CBP in yeast, HeLa, human embryonic kidney 293 and CV-1 cells. GRIP1 (with a deletion of site II) expressed stronger co-activator activity than that of wild-type GRIP1 in the TR (thyroid receptor) and the AR (androgen receptor), but not the ER (oestrogen receptor), systems in HeLa cells. We also demonstrated that these CBP-binding sites of GRIP1 are not the only functional domains for its AD1 function in TR, AR and ER systems in HeLa cells by the exogenous overexpression of one E1A mutant, which led to a lack of CBP-binding ability. Our results suggest that these two CBP-interacting sites in the GRIP AD1 domain not only determine its AD1 activity, but are also involved in its co-activator functions in some nuclear receptors.

The nuclear-receptor interacting protein (RIP) 140 binds to the human glucocorticoid receptor and modulates hormone-dependent transactivation

1999 ◽  
Vol 71 (3-4) ◽  
pp. 93-102 ◽  
Author(s):  
Sara H Windahl ◽  
Eckardt Treuter ◽  
Jacqueline Ford ◽  
Johanna Zilliacus ◽  
Jan-Åke Gustafsson ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Nuclear Receptor ◽  
Interacting Protein
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