Discovery of Proteolysis-Targeting Chimera Molecules that Selectively Degrade the IRAK3 Pseudokinase

Abstract

We report the first disclosure of IRAK3 degraders in the scientific literature. Taking advantage of an opportune by-product obtained during our efforts to identify IRAK4 inhibitors, we identified ready to use, selective IRAK3 ligands in our compound collection with the required properties for conversion into PROTAC degraders. This work culminated with the discovery of PROTAC 23, which we demonstrated to be a potent and selective degrader of IRAK3. 23 induced proteasome-dependent degradation of IRAK3 and required both CRBN and IRAK3 binding for activity. We conclude that PROTAC 23 constitutes an excellent in vitro tool with which to interrogate the biology of IRAK3.