Lanthanide ions (e.g. Tb3+, Eu3+) emit long-lived luminescence that can be measured in a time-resolved fashion, effectively eliminating background fluorescence from biological samples. We exploit this property to develop peptide-based biosensors for kinase activity that are compatible with high-throughput plate-reader formats.
Our approach uses a peptide substrate that, upon phosphorylation, undergoes a conformational change bringing a sensitizing antenna chromophore into proximity with a lanthanide chelate, triggering a large increase in luminescence signal. This ratiometric, mix-and-read format requires no separation steps or secondary reagents, making it well suited to screening large compound libraries.
We have applied lanthanide luminescence assays to multiple tyrosine kinases including ALK, Abl, and Syk, and have used the platform to screen inhibitor panels and characterize substrate selectivity in cell lysates and intact cells.