PROTAC 20S proteasome subunit β5 degrader 2 is a PROTAC degrader for 20S proteasome subunit β5 , with a DC 50 of 0.16 μM. PROTAC 20S proteasome subunit β5 degrader 2 inhibits the proliferation of cancer cell FaDu with IC 50 of 0.23 μM. PROTAC 20S proteasome subunit β5 degrader 2 exhibits antitumor efficacy in mice models. (Pink: Ligand for target protein ; Blue: Ligand for E3 ligase ; Black: Linker )