Assay Method Information | |
| Biological Assays |
Description: | The compounds of the invention inhibit RORgammaT activity. Activation of RORgammaT activity can be measured using, e.g., biochemical TR-FRET assay. In such an assay, interaction of cofactor-derived peptides with human RORgammaT-Ligand Binding Domain (LBD) can be measured. The TR-FRET technique is a sensitive biochemical proximity assay that will give information concerning the interaction of a ligand with the LBD, in the presence of cofactor-derived peptides (Zhou et al., Methods 25:54-61, 2001).To identify novel antagonists of RORgammaT, an assay was developed which employs the interaction of RORgammaT with its co-activator peptide SRC1_2. This peptide mimics the recruitment of co-activators to RORgammaT through its interaction with the LXXLL (SEQ ID NO:1) (e.g., NR box) motifs (Xie et al., J. Immunol. 175: 3800-09, 2005; Kurebayashi et al., Biochem. Biophys. Res. Commun. 315: 919-27, 2004; Jin et al., Mol. Endocrinology 24:923-29, 2010). The RORγ-Ligand Binding Domain TR-FRET Assay was run according to the following protocol.HIS-tagged RORγ-LBD protein was expressed in SF9 cells using a baculovirus expression system. The RORγ-LBD protein was purified by glutathione sepharose chromatography. Separately, SF9 cells not expressing any recombinant protein were lysed and the lysate was added to the purified RORγ-LBD at 0.25 μl lysate (from 10,000 SF9 cells)/nM purified protein. The mixture was then diluted in assay buffer (50 mM Tris pH 7.0, 50 mM KCl, 1 mM EDTA, 0.1 mM DTT) to obtain RORγ-LBD final concentration of 3 nM in 384-well assay plate.Compounds to be tested were injected to the assay plate using Acoustic Droplet Ejection technology by Echo 550 liquid handler (Labcyte, Calif.).A stock of biotinylated-LXXLL peptide from coactivator SRC1 (Biotin-CPSSHSSLTERHKILHRLLQEGSPS) (SEQ ID NO:2) was prepared in assay buffer and added to each well (100 nM final concentration). A solution of Europium tagged anti-HIS antibody (1.25 nM final concentration) and APC conjugated streptavidin (8 nM final concentration) were also added to each well.The final assay mixture was incubated overnight at 4° C., and the fluorescence signal was measured on an Envision plate reader: (Excitation filter=340 nm; APC emission=665 nm; Europium emission=615 nm; dichroic mirror=D400/D630; delay time=100 μs, integration time=200 μs). IC50 values for test compounds were calculated from the quotient of the fluorescence signal at 665 nm divided by the fluorescence signal at 615 nm. |
Affinity data for this assay | |
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