Invitrogen™ FL - SRC 1-4 Peptide

Ligand binding to nuclear receptors causes conformational changes in the receptor, resulting in a cascade of events, including dissociation of repressor proteins, association of coactivator proteins, and assembly of pol II and other transcriptional factors for activation of target genes. TR-FRET based assays can be developed using the LanthaScreen™ panel of fluorescein-labeled coregulator peptides to investigate conformational changes of nuclear receptors upon ligand binding, either by determining the affinity of ligand-bound receptor for different coregulator peptides, or by identifying additional agonists or antagonists via displacement or recruitment of a specific coregulator peptide.

In the LanthaScreen™ TR-FRET RXR beta Coactivator Assay, a terbium (Tb)-labeled anti-GST antibody is used to indirectly label GSTtagged RXR beta protein. An agonist (9-cis Retinoic Acid) added to the receptor which, upon ligand binding, causes a conformational change resulting in recruitment of the Fl-D22 coactivator peptide. The binding of the fluorescent coregulator peptide to RXR beta causes an increase in the TR-FRET emission ratio.