p23 co-chaperone protects the aryl hydrocarbon receptor from degradation in mouse and human cell lines

Nguyễn, Phương Ngọc; Wang, Depeng; Wang, Yu; Li, Yanjie; Uchizono, James A.; Chan, William K.

doi:10.1016/j.bcp.2012.06.018

Cited by 18 publications

(25 citation statements)

References 48 publications

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“…The best known mechanisms that trigger the AHR proteasomal degradation are mediated through binding of a ligand [21] and treatment with an Hsp90 inhibitor such as geldanamycin [22]. In addition, we have reported that down-regulation of p23 causes degradation of the AHR protein in various mouse and human cell lines [23]. Here we present data supporting that this p23 effect is not merely changing the dynamics of the AHR cytoplasmic complex.…”

Section: Introductionsupporting

confidence: 70%

p23 protects the human aryl hydrocarbon receptor from degradation via a heat shock protein 90-independent mechanism

Pappas

Yang

Wang

et al. 2018

Biochemical Pharmacology

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The aryl hydrocarbon receptor (AHR) is a ligand-activated signaling molecule which is involved in diverse biological functions ranging from cancer metastasis to immune regulation. This receptor forms a cytoplasmic complex with Hsp90, p23, and XAP2. We have previously reported that down-regulation of p23 triggers degradation of the AHR protein, uncovering a potentially dynamic event which controls the cellular AHR levels without ligand treatment. Here we investigate the underlying mechanisms for this p23 effect using wild-type HeLa and the p23 knockdown HeLa cells. Reduction of the Hsp90 and XAP2 contents, however, did not affect the AHR protein levels, implying that this p23 effect on AHR is more than just alteration of the cytoplasmic complex dynamics. Association of p23 with Hsp90 is not important for the modulation of the AHR levels since exogenous expression of p23 mutants with modest Hsp90-binding affinity effectively restored the AHR message and protein levels. The protein folding property of p23 which resides at the terminal 50-amino acid region is not involved for this p23 effect. Results from our interaction study using the affinity purified thioredoxin fusion proteins and GST fusion proteins showed that p23 directly interacts with AHR and the interaction surface lies within AHR amino acid 1-216 and p23 amino acid 1-110. Down-regulation of the p23 protein content promotes the ubiquitination of AHR, indicating that p23 protects AHR from the ubiquitin-meditated protein degradation.

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Section: Introductionsupporting

confidence: 70%

p23 protects the human aryl hydrocarbon receptor from degradation via a heat shock protein 90-independent mechanism

Pappas

Yang

Wang

et al. 2018

Biochemical Pharmacology

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“…1A). In the cytoplasm, the ligand-free AHR is in a complex with two HSP90 molecules, at least one p45 protein identified as an immunophilin [10, 11], and the co-chaperone p23 protein [12]. In canonical AHR signaling, ligand binding alters the complex allowing the translocation of the AHR to the nucleus and partnering with the aryl hydrocarbon nuclear translocator (ARNT).…”

Section: Introductionmentioning

confidence: 99%

Obesity and fatty liver are prevented by inhibition of the aryl hydrocarbon receptor in both female and male mice

et al. 2017

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Inhibition of the aryl hydrocarbon receptor (AHR) prevents Western diet-induced obesity and fatty liver in C57Bl/6J (B6) male mice. The AHR is a ligand-activated nuclear receptor that regulates genes involved in xenobiotic metabolism and T cell differentiation. Here, we tested the hypothesis that AHR antagonism would also prevent obesity and fatty liver in female mice and that B6 mice (higher-affinity AHR) and congenic B6.D2 mice (lower-affinity AHR) would differentially respond to AHR inhibition. Female and male adult B6 and B6.D2 mice were fed control and Western diets with and without α-naphthoflavone, an AHR inhibitor. A nonlinear mixed model analysis was developed to project asymptote body mass. We found that obesity, adiposity, and liver steatosis were reduced to near control levels in all female and male B6 and B6.D2 experimental groups fed Western diet with α-naphthoflavone. However, differences were noted in that female B6.D2 versus B6 mice on Western diet became more obese; and in general, female mice to that of male mice had a greater fat mass to body mass ratio, were less responsive to α-naphthoflavone, and had reduced liver steatosis and hepatomegaly. We report that male mice fed Western diet containing α-naphthoflavone or CH-223191, another AHR inhibitor, caused reduced mRNA levels of several liver genes involved in metabolism, including Cyp1b1 and Scd1, offering evidence for a possible mechanism by which the AHR regulates obesity. In conclusion, although there are some sex- and Ahr allelic-dependent differences, AHR inhibition prevents obesity and liver steatosis in both males and females regardless of the ligand-binding capacity of the AHR. We also present evidence consistent with the notion that an AHR-CYP1B1-SCD1 axis is involved in obesity providing potentially convenient and effective targets for treatment.

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“…We conducted similar gel shift experiment which we routinely performed to observe the ligand-dependent formation of the AHR gel shift complex from nuclear extracts and the baculovirus expressed AHR and ARNT proteins [22, 23]. Results from the gel shift assay showed that GA-hAHR can effectively form a gel shift complex with GA-hARNT in a ligand-dependent manner (Fig.…”

Section: Resultsmentioning

confidence: 99%

Binding studies using Pichia pastoris expressed human aryl hydrocarbon receptor and aryl hydrocarbon receptor nuclear translocator proteins

Zheng

Xie

Huang

et al. 2016

Protein Expression and Purification

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The aryl hydrocarbon receptor (AHR) is a transcription factor which activates gene transcription by binding to its corresponding enhancer as the heterodimer, which is consisted of AHR and the aryl hydrocarbon receptor nuclear translocator (ARNT). Human AHR can be rather difficult to study, when compared among the AHR of other species, since it is relatively unstable and less sensitive to some ligands in vitro. Overexpression of human AHR has been limited to the baculovirus expression, which is costly and tedious due to the need of repetitive baculovirus production. Here we explored whether we could generate abundant amounts of human AHR and ARNT in a better overexpression system for functional study. We observed that human AHR and ARNT can be expressed in Pichia pastoris with yields that are comparable to the baculovirus system only if their cDNAs are optimized for Pichia expression. Fusion with a c-myc tag at their C-termini seems to increase the expression yield. These Pichia expressed proteins can effectively heterodimerize and form the ternary AHR/ARNT/enhancer complex in the presence of β-naphthoflavone or kynurenine. Limited proteolysis using thermolysin can be used to study the heterodimerization of these human AHR and ARNT proteins.

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p23 co-chaperone protects the aryl hydrocarbon receptor from degradation in mouse and human cell lines

Cited by 18 publications

References 48 publications

p23 protects the human aryl hydrocarbon receptor from degradation via a heat shock protein 90-independent mechanism

p23 protects the human aryl hydrocarbon receptor from degradation via a heat shock protein 90-independent mechanism

Obesity and fatty liver are prevented by inhibition of the aryl hydrocarbon receptor in both female and male mice

Binding studies using Pichia pastoris expressed human aryl hydrocarbon receptor and aryl hydrocarbon receptor nuclear translocator proteins

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