Summary: The TR-FRET Vitamin D Receptor (VDR) Coactivator Assay Kit provides a sensitive and robust method for high-throughput screening of potential VDR ligands as agonists of coactivator recruitment. The kit uses a terbium (Tb)-labeled anti-GST antibody, a fluorescein-labeled coactivator peptide, and a VDR ligand-binding domain (VDR-LBD) that is tagged with glutathione-S-transferase (GST), in a homogenous mix-and-read assay format.