Regulation of pregnane X receptor (PXR) function and UGT1A1 gene expression by posttranslational modification of PXR protein

doi:10.1124/dmd.112.046748

	Regulation of pregnane X receptor (PXR) function and UGT1A1 gene expression by posttranslational modification of PXR protein
	Sugatani, Junko; Uchida, Takahiro; Kurosawa, Masatoshi; Yamaguchi, Masahiko; Yamazaki, Yasuhiro; Ikari, Akira; Miwa, Masao
刊名	Drug metabolism and disposition: the biological fate of chemicals
	2012-10
卷号	40 期号:10 页码:2031-40
ISSN号	1521-009X
DOI	10.1124/dmd.112.046748
文献子类	Article
英文摘要	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.
语种	英语
内容类型	期刊论文
源URL	[http://119.78.100.183/handle/2S10ELR8/266710]
专题	中国科学院上海药物研究所
通讯作者	Sugatani, Junko
作者单位	Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
推荐引用方式 GB/T 7714	Sugatani, Junko,Uchida, Takahiro,Kurosawa, Masatoshi,et al. Regulation of pregnane X receptor (PXR) function and UGT1A1 gene expression by posttranslational modification of PXR protein[J]. Drug metabolism and disposition: the biological fate of chemicals,2012,40(10):2031-40.
APA	Sugatani, Junko.,Uchida, Takahiro.,Kurosawa, Masatoshi.,Yamaguchi, Masahiko.,Yamazaki, Yasuhiro.,...&Miwa, Masao.(2012).Regulation of pregnane X receptor (PXR) function and UGT1A1 gene expression by posttranslational modification of PXR protein.Drug metabolism and disposition: the biological fate of chemicals,40(10),2031-40.
MLA	Sugatani, Junko,et al."Regulation of pregnane X receptor (PXR) function and UGT1A1 gene expression by posttranslational modification of PXR protein".Drug metabolism and disposition: the biological fate of chemicals 40.10(2012):2031-40.