Fig. 6.

Subcellular localization of Thr408 mutant PXR proteins. CV-1 cells were cotransfected with constructs expressing wild-type and mutant GFP-PXR fusion proteins. Twenty-four hours after transfection, cells were treated with either vehicle or 10 μM rifampicin. The subcellular localization of GFP-PXR protein was observed by fluorescence microscopy for an additional 24 h after drug treatment. A, treatment with rifampicin resulted in the complete translocation of wild-type GFP-hPXR to the nuclear compartment. B, phosphomimetic mutation at Thr408 resulted in a punctate distribution of GFP-T408D in the cytoplasm and nucleus both in the presence of vehicle or rifampicin treatment. C, the phosphodeficient GFP-T408A PXR protein was not excluded from the cytoplasmic compartment upon rifampicin treatment. DAPI, 4,6-diamidino-2-phenylindole-2-HCl; VEH, vehicle; RIF, rifampicin.