Abstract

The PROteolysis Targeting Chimera (PROTAC) technology is expanding as a new modality in drug discovery. This increasing interest requires high-throughput protein degradation assays to complement the labour-intensive and slow Western Blot protein quantification. We developed a high-throughput plate-based AlphaLISA assay for target engagement and modified it for rapid measurement of target degradation in different cell backgrounds. In this assay we observed time- and concentration dependent degradation of the target protein with variations depending on which E3 ligase was recruited. We also showed good translation between a monocyte cell line (THP-1) and disease relevant primary cells. The kinase of interest is expressed in many tissues and selectivity among isoforms and in the wider kinome is challenging. The PROTAC approach may provide additional means to gain selectivity over other kinases and we are currently establishing a panel of HiBiT assays to generate selectivity profiles for the PROTAC compounds.