| RRC ID |
43972
|
| 著者 |
Sugatani J, Uchida T, Kurosawa M, Yamaguchi M, Yamazaki Y, Ikari A, Miwa M.
|
| タイトル |
Regulation of pregnane X receptor (PXR) function and UGT1A1 gene expression by posttranslational modification of PXR protein.
|
| ジャーナル |
Drug Metab Dispos
|
| Abstract |
Human UDP-glucuronosyltransferase (UGT) 1A1 is a critical enzyme responsible for detoxification and metabolism of endogenous and exogenous lipophilic compounds such as bilirubin. The present study shows how cyclin-dependent kinase (CDK) inhibitor roscovitine stimulated the expression of UGT1A1 in HepG2 cells. Pregnane X receptor (PXR)-mediated transactivation of UGT1A1 reporter gene was more prominently enhanced by roscovitine, compared with the basal-, constitutive androstane receptor (CAR)-, and aryl hydrocarbon receptor-mediated activities. We determined the regulatory mechanism of UGT1A1 expression through PXR's stimulation by roscovitine. Although phosphomimetic mutations at Thr290 and Thr408 retained the PXR protein in cytoplasm and attenuated the induction of UGT1A1 expression by both roscovitine and rifampicin, a mutation at Ser350 specifically reduced the activity of PXR induced by roscovitine. Immunoprecipitation analysis revealed that the T290D but not T408D mutant protein remained in cytoplasm by forming a complex with heat shock protein 90 and cytoplasmic CAR retention protein, whereas treatment with proteasome inhibitor MG-132 accumulated the T408D mutant protein in cytoplasm. Transfection with anti-CDK2 small interfering RNA (siRNA) but not anti-CDK1 or CDK5 siRNA led to enhanced expression of UGT1A1. S350D yellow fluorescent protein-PXR fusion protein could translocate from cytoplasm to nucleus similar to the wild-type protein but was detected as an acetylated protein, whose binding with retinoid X receptor (RXR) and histone deacetylase was impaired. Cotransfection with coactivator steroid receptor coactivator (SRC) 2 but not SRC-1 partly recovered its PXR activity. These results indicate that roscovitine stimulated the expression of UGT1A1 by inhibiting CDK2, which phosphorylated PXR at Ser350 to suppress binding with RXR and coactivator and maintain the acetylation of PXR protein.
|
| 巻・号 |
40(10)
|
| ページ |
2031-40
|
| 公開日 |
2012-10-1
|
| DOI |
10.1124/dmd.112.046748
|
| PII |
dmd.112.046748
|
| PMID |
22829544
|
| MeSH |
Acetylation
Basic Helix-Loop-Helix Transcription Factors / metabolism
Constitutive Androstane Receptor
Cyclin-Dependent Kinase 2 / antagonists & inhibitors
Cyclin-Dependent Kinase 2 / metabolism
Dose-Response Relationship, Drug
Down-Regulation
Gene Expression Regulation, Enzymologic
Glucuronosyltransferase / genetics
Glucuronosyltransferase / metabolism*
HSP40 Heat-Shock Proteins / metabolism
HSP90 Heat-Shock Proteins / metabolism
Heat-Shock Proteins
Hep G2 Cells
Humans
Immunoprecipitation
Molecular Chaperones
Mutation
Nuclear Receptor Coactivator 2 / metabolism
Phosphorylation
Pregnane X Receptor
Protein Kinase Inhibitors / pharmacology
Protein Processing, Post-Translational* / drug effects
Protein Transport
Purines / pharmacology
RNA Interference
Receptors, Aryl Hydrocarbon / metabolism
Receptors, Cytoplasmic and Nuclear / metabolism
Receptors, Steroid / drug effects
Receptors, Steroid / genetics
Receptors, Steroid / metabolism*
Retinoid X Receptors / metabolism
Rifampin / pharmacology
Roscovitine
Serine
Time Factors
Transcriptional Activation
Transfection
|
| IF |
3.231
|
| 引用数 |
28
|
|
WOS 分野
|
PHARMACOLOGY & PHARMACY
|
| リソース情報 |
| ヒト・動物細胞 |
Hep G2 |
