Substrate specificity

Gene

Cell biology

Biology

Proteolysis

Ubiquitin ligase

Biochemistry

Protein structure

Ternary complex

DNA ligase

Ubiquitin

Computational biology

Enzyme

Ubiquitin-Protein Ligases

Chemistry

Proteasome

Protein degradation

Annual Review of Biochemistry

Methods to direct the degradation of protein targets with proximity-inducing molecules that coopt the cellular degradation machinery are advancing in leaps and bounds, and diverse modalities are emerging. The most used and well-studied approach is to hijack E3 ligases of the ubiquitin-proteasome system. E3 ligases use specific molecular recognition to determine which proteins in the cell are ubiquitinated and degraded. This review focuses on the structural determinants of E3 ligase recruitment of natural substrates and neo-substrates obtained through monovalent molecular glues and bivalent proteolysis-targeting chimeras. We use structures to illustrate the different types of substrate recognition and assess the basis for neo-protein-protein interactions in ternary complex structures. The emerging structural and mechanistic complexity is reflective of the diverse physiological roles of protein ubiquitination. This molecular insight is also guiding the application of structure-based design approaches to the development of new and existing degraders as chemical tools and therapeutics.

Driving E3 Ligase Substrate Specificity for Targeted Protein Degradation: Lessons from Nature and the Laboratory