Role of the Per/Arnt/Sim Domains in Ligand-dependent Transformation of the Aryl Hydrocarbon Receptor

Soshilov, Anatoly A.; Denison, Michael S.

doi:10.1074/jbc.m802414200

Cited by 74 publications

(113 citation statements)

References 45 publications

Supporting

Mentioning

103

Contrasting

Unclassified

Order By: Relevance

“…When AhR is activated by chemicals, AhR translocates into the nucleus. Then, this transcription factor heterodimerizes with ARNT in the nucleus and the resulting complex binds to the XRE on DNA (Fujisawa-Sehara et al, 1987;Soshilov and Denison, 2008). Consistent with this, treatment with TBQ, 1,2-NQ, 1,2-BQ, 1,4-NQ and 1,2-NQ all caused translocation of AhR into the nucleus in Hepa1c1c7 cells detected by immunostaining and Western blotting using nuclear fraction (data not shown).…”

Section: Role Of Ahr In Cyp1a1 Induction By Mono-and Bi-aromatic Hydrsupporting

confidence: 65%

Covalent binding of quinones activates the Ah receptor in Hepa1c1c7 cells

2015

View full text Add to dashboard Cite

-Highly reactive quinone species produced by photooxidation and/or metabolic activation of mono-or bi-aromatic hydrocarbons modulate cellular homeostasis and electrophilic signal transduction pathways through the covalent modification of proteins. Polycyclic aromatic hydrocarbons, but not mono-or bi-aromatic hydrocarbons, are well recognized as ligands for the aryl hydrocarbon receptor (AhR). However, quinone species produced from mono-and bi-aromatic hydrocarbons could potentially cause AhR activation. To clarify the AhR response to mono-and bi-aromatic hydrocarbon quinones, we studied Cyp1a1 (cytochrome P450 1A1) induction and AhR activation by these quinones. We detected Cyp1a1 induction during treatment with quinones in Hepa1c1c7 cells, but not their parent compounds. Nine of the twelve quinones with covalent binding capability for proteins induced Cyp1a1. Cyp1a1 induction mediated by 1,2-naphthoquinone (1,2-NQ), 1,4-NQ, 1,4-benzoquinone (1,4-BQ) and tert-butyl-1,4-BQ was suppressed by a specific AhR inhibitor and was not observed in c35 cells, which do not have a functional AhR. These quinones stimulated AhR nuclear translocation and interaction with the AhR nuclear translocator. Interestingly, 1,2-NQ covalently modified AhR, which was detected by an immunoprecipitation assay using a specific antibody against 1,2-NQ, resulting in enhancement of xenobiotic responsive element (XRE)-derived luciferase activity and binding of AhR to the Cyp1a1 promoter region. While mono-and bi-aromatic hydrocarbons are generally believed to be poor ligands for AhR and hence unable to induce Cyp1a1, our study suggests that the quinones of these molecules are able to modify AhR and activate the AhR/XRE pathway, thereby inducing Cyp1a1. Since we previously reported that 1,2-NQ and tert-butyl-1,4-BQ also activate NF-E2-related factor 2, it seems likely that some of quinones are bi-functional inducers for phase-I and phase-II reaction of xenobiotics.

show abstract

Section: Role Of Ahr In Cyp1a1 Induction By Mono-and Bi-aromatic Hydrsupporting

confidence: 65%

Covalent binding of quinones activates the Ah receptor in Hepa1c1c7 cells

2015

View full text Add to dashboard Cite

show abstract

“…Wild-type (wt) and mutant AhRs were synthesized in vitro in the presence of L-methionine or [ 35 S]L-methionine (PerkinElmer) using the TNT Quick coupled transcription/translation rabbit reticulocyte lysate kit (Promega). To compare relative expression levels of each mutant AhR, aliquots of in vitro synthesized 35 S-labeled wt and mutant AhR protein were analyzed by SDS-PAGE as previously described (39). Unlabeled AhR and ARNT were used for functional analysis studies.…”

Section: Methodsmentioning

confidence: 99%

“…m␤AhR/pcDNA3 and m␤Arnt/pcDNA3 have been previously described (38,39). Point mutations of m␤AhR/pcDNA3 were carried out using the QuikChange technique (Stratagene).…”

Section: Methodsmentioning

confidence: 99%

Ligand Promiscuity of Aryl Hydrocarbon Receptor Agonists and Antagonists Revealed by Site-Directed Mutagenesis

Soshilov

Denison

2014

Molecular and Cellular Biology

Self Cite

112

106

View full text Add to dashboard Cite

The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor that can be activated by structurally diverse chemicals. To examine the mechanisms responsible for the promiscuity in AhR ligand binding, we determined the effects of mutations within the AhR ligand-binding domain (LBD) on the activity of diverse AhR ligands. Site-directed mutagenesis identified Ile319 of the mouse AhR and, to a lesser extent, Phe318 as residues involved in ligand-selective modulation of AhR transformation using a panel of 12 AhR ligands. These ligands could be categorized into four distinct structurally related groups based on their ability to activate AhR mutants at position 319 in vitro. The mutation I319K was selectively activated by FICZ and not by other examined ligands in vitro and in cell culture. F318L and F318A mutations resulted in the conversion of AhR agonists ␤-naphthoflavone and 3-methylcholanthrene, respectively, into partial agonists/antagonists. Hsp90 binding to the AhR was decreased with several mutations and was inversely correlated with AhR ligand-binding promiscuity. Together, these data define overlapping amino acid residues within the AhR LBD involved in the selectivity of ligand binding, the agonist or antagonist mode of ligand binding, and hsp90 binding and provide insights into the ligand diversity of AhR activators.

show abstract

“…Many of the Per-ARNT-Sim proteins sense molecules and stimuli from the cellular/tissue environment and initiate signaling cascades to elicit appropriate cellular responses. Lipophilic compounds such as halogenated and polycyclic aromatic hydrocarbons, including the potent exogenous ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (Poland and Glover 1973), bind to the cytoplasmic AhR, leading to a sequence of conformational changes that ultimately transform the AhR into its high-affinity DNA binding form in the nucleus to function as a transcription factor (Soshilov and Denison 2008).…”

Section: Introductionmentioning

confidence: 99%

Aryl Hydrocarbon Receptor Activation in Hematopoietic Stem/Progenitor Cells Alters Cell Function and Pathway-Specific Gene Modulation Reflecting Changes in Cellular Trafficking and Migration

Casado¹,

Singh²,

Gasiewicz³

2011

Mol Pharmacol

View full text Add to dashboard Cite

The aryl hydrocarbon receptor (AhR) is a transcription factor belonging to the Per-ARNT-Sim family of proteins. These proteins sense molecules and stimuli from the cellular/tissue environment and initiate signaling cascades to elicit appropriate cellular responses. Recent literature reports suggest an important function of AhR in hematopoietic stem cell (HSC) biology. However, the molecular mechanisms by which AhR signaling regulates HSC functions are unknown. In previous studies, we and others reported that treatment of mice with the AhR agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) compromises the competitive reconstitution of bone marrow (BM) cells into irradiated host animals. Additional studies indicated a requirement for AhR in hematopoietic cells and not marrow microenvironment cells. In this study, we tested the hypothesis that TCDDmediated phenotypic and functional changes of HSCs are a result of changes in gene expression that disrupt stem cell numbers and/or their migration. TCDD treatment to mice increased the numbers of phenotypically defined HSCs in BM. These cells showed compromised migration to the BM in vivo and to the chemokine CXCL12 in vitro, as well as increased expression of the leukemia-associated receptors CD184 (CXCR4) and CD44. Gene expression profiles at 6 and 12 h after exposure were consistent with the phenotypic and functional changes observed. The expressions of Scin, Nqo1, Flnb, Mmp8, Ilf9, and Slamf7 were consistently altered. TCDD also disrupted expression of other genes involved in hematological system development and function including Fos, JunB, Egr1, Ptgs2 (Cox2), and Cxcl2. These data support a molecular mechanism for an AhR ligand to disrupt the homeostatic cell signaling of HSCs that may promote altered HSC function.

show abstract

Role of the Per/Arnt/Sim Domains in Ligand-dependent Transformation of the Aryl Hydrocarbon Receptor

Cited by 74 publications

References 45 publications

Covalent binding of quinones activates the Ah receptor in Hepa1c1c7 cells

Covalent binding of quinones activates the Ah receptor in Hepa1c1c7 cells

Ligand Promiscuity of Aryl Hydrocarbon Receptor Agonists and Antagonists Revealed by Site-Directed Mutagenesis

Aryl Hydrocarbon Receptor Activation in Hematopoietic Stem/Progenitor Cells Alters Cell Function and Pathway-Specific Gene Modulation Reflecting Changes in Cellular Trafficking and Migration

Contact Info

Product

Resources

About