Our review covering E3 ligase ligands for PROTACs is now published in SLAS Discovery

  • SLAS Discovery journal cover
  • Figure 1. Graphical representation of the degradation mechanism of proteolysis-targeting chimeras (PROTACs).
  • Figure 2. Von Hippel–Lindau (VHL)-based and cereblon (CRBN)-based small-molecule proteolysis-targeting chimeras (PROTACs).
  • Figure 3. Representative structures and biological data of recently disclosed patents
  • Figure 4. Inhibitor of apoptosis protein (IAP)-based and mouse double minute 2 homolog (MDM2)-based proteolysis-targeting chimeras (PROTACs), and von Hippel–Lindau (VHL)-based and cereblon (CRBN)-based homo-PROTACs.
  • Figure 5. Proteolysis-targeting chimeras (PROTACs) using nonconventional E3 ligase ligands.
  • Figure 6. Noncovalent and covalent fragment-based approaches for hit finding and ligand development for E3 ligases.
  • Table 1. List of E3 ligases of potential use for PROTACs

Congratulations to Tasuku on this article. We hope people will find this review useful!

Read the Open Access full article here.

Authors: Tasuku Ishida and Alessio Ciulli*

Title: E3 Ligase Ligands for PROTACs: How They Were Found and How to Discover New Ones


Bifunctional degrader molecules, also called proteolysis-targeting chimeras (PROTACs), are a new modality of chemical tools and potential therapeutics to understand and treat human disease. A required PROTAC component is a ligand binding to an E3 ubiquitin ligase, which is then joined to another ligand binding to a protein to be degraded via the ubiquitin–proteasome system. The advent of nonpeptidic small-molecule E3 ligase ligands, notably for von Hippel–Lindau (VHL) and cereblon (CRBN), revolutionized the field and ushered in the design of drug-like PROTACs with potent and selective degradation activity. A first wave of PROTAC drugs are now undergoing clinical development in cancer, and the field is seeking to extend the repertoire of chemistries that allow hijacking new E3 ligases to improve the scope of targeted protein degradation.  Here, we briefly review how traditional E3 ligase ligands were discovered, and then outline approaches and ligands that have been recently used to discover new E3 ligases for PROTACs. We will then take an outlook at current and future strategies undertaken that invoke either target-based screening or phenotypic-based approaches, including the use of DNA-encoded libraries (DELs), display technologies and cyclic peptides, smaller molecular glue degraders, and covalent warhead ligands. These approaches are ripe for expanding the chemical space of PROTACs and usher in the advent of other emerging bifunctional modalities of proximity-based pharmacology.