For the design of bifunctional degraders, we drew from the structure-activity correlations previously established for PDE ligands deltazinone and deltasonamide and PDE PROTACs based on these two PDE ligands (Supplementary Fig. ). Protein-ligand complex crystal structures and a docking model GW5074 had been identified as LC3B binder after immobilization on a solid support through the phenolic OH-group suggesting that a linker could be attached at this site .