Rapamycin-LC-Fluorescein

Rapamycin-LC-Fluorescein is an excellent fluorescent probe to characterize FK506-binding proteins by fluorescence polarization. It has moderate affinity for the FK1 domains of FKBP51 (177 nM) and FKBP2 (469 nM). It can be used for active-site titrations, competition assays with unlabeled ligands and enable a robust, miniaturized assay adequate for high-throughput screening. FK506-binding proteins (FKBPs) convey the immunosuppressive action of FK506 and rapamycin and mediate the neuroprotective properties of these compounds and participate in the regulation of calcium channels. In addition, the larger homologues FKBP51 and FKBP52 act as cochaperones for Hsp90 and regulate the transactivation activity of steroid hormone receptors.