The significance of phosphorylation for FXR

The serine or threonine between two zinc fingers of the DNA binding domains (DBD) is highly conserved in a majority of nuclear receptors. In the present study, we focused on the serine 154 of farnesoid X receptor (FXR). To determine the influence of phosphomimetic or non-phosphomimetic mutation for FXR on gene expressions, we employed cDNA microarray analysis using COS-1 cells which ectopically express FXR S154A or FXR S154D with DMSO or CDCA. COS-1 cells were transfected with human FXR S154A mutant or its S154D for 24 hr. The cells were subsequently incubated with 0.1%DMSO or 50 mMCDCA for 24 hr. Three replicates were used for each treatment group.

大多数核受体的DNA结合结构域（DNA binding domains, DBD）中，两个锌指结构之间的丝氨酸或苏氨酸位点高度保守。本研究聚焦于法尼醇X受体（farnesoid X receptor, FXR）的丝氨酸154位点。为探明拟磷酸化突变与非拟磷酸化突变对FXR基因表达的影响，我们采用异位表达FXR S154A或FXR S154D的COS-1细胞，分别以二甲基亚砜（dimethyl sulfoxide, DMSO）或鹅脱氧胆酸（chenodeoxycholic acid, CDCA）处理后进行cDNA微阵列分析。将COS-1细胞转染人源FXR S154A突变体或其S154D突变体，培养24小时；随后将细胞分别置于0.1% DMSO或50 mM CDCA环境中孵育24小时。每个处理组均设置三次生物学重复。