Hijacking ERAD for targeted degradation of transmembrane proteins.

Targeted protein degradation (TPD) technologies provide huge opportunities for drug discovery, but degrading transmembrane (TM) targets remains challenging. Since TM proteins are canonically folded on the endoplasmic reticulum (ER) membrane, we hypothesized that harnessing ER-associated degradation (ERAD) may enable efficient degradation of TM proteins. Here, we established a TPD technology hijacking ERAD and named it ERAD-engaging chimeras (ERADECs), capable of degrading TM targets with high efficacy. We identified desonide as a binder of SYVN1, an ER E3 ligase mediating ERAD. We designed ERADECs targeting programmed death-ligand 1 (PD-L1) by connecting desonide to a known PD-L1 ligand and observed SYVN1- and ERAD-dependent PD-L1 degradation with high efficacy. Functionally, these ERADECs exhibited stronger tumor suppression and PD-L1-lowering effects than a clinically used PD-L1 antibody in vivo. The concept of ERADECs is also expandable to other membrane targets. Collectively, we established a platform technology hijacking ERAD to selectively degrade TM targets with remarkable efficiency.