Journal Article

Differential PROTAC substrate specificity dictated by orientation of recruited E3 ligase

Hamman, Brian D., Wang, Stephen L., Harbin, Alicia, Smith, Blake E., Crews, Craig M., Jaime-Figueroa, Saul, Wang, Jing

2019

Overview

PROteolysis-TArgeting Chimeras (PROTACs) are hetero-bifunctional molecules that recruit an E3 ubiquitin ligase to a given substrate protein resulting in its targeted degradation. Many potent PROTACs with specificity for dissimilar targets have been developed; however, the factors governing degradation selectivity within closely-related protein families remain elusive. Here, we generate isoform-selective PROTACs for the p38 MAPK family using a single warhead (foretinib) and recruited E3 ligase (von Hippel-Lindau). Based on their distinct linker attachments and lengths, these two PROTACs differentially recruit VHL, resulting in degradation of p38α or p38δ. We characterize the role of ternary complex formation in driving selectivity, showing that it is necessary, but insufficient, for PROTAC-induced substrate ubiquitination. Lastly, we explore the p38δ:PROTAC:VHL complex to explain the different selectivity profiles of these PROTACs. Our work attributes the selective degradation of two closely-related proteins using the same warhead and E3 ligase to heretofore underappreciated aspects of the ternary complex model. PROTACs enable targeted protein degradation by recruiting an E3 ligase to a specific substrate but the determinants of selectivity are not fully understood. Here, the authors show that varying the linker between warhead and E3 ligand and the orientation of the E3 ligase allow tuning PROTAC selectivity toward different p38 isoforms.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Portfolio
• Subject: 13/106 / 631/92/458/582 / 631/92/609 / 631/92/613 / 631/92/96 / Biodegradation / Chimeras / Complex formation / Degradation / Humanities and Social Sciences / Humans / MAP kinase / Models, Molecular / Molecular Structure / multidisciplinary / Neoplasia / p38 Mitogen-Activated Protein Kinases - chemistry / p38 Mitogen-Activated Protein Kinases - metabolism / Protein Domains / Protein families / Proteins / Proteolysis / Proteolysis - drug effects / Science / Science (multidisciplinary) / Selectivity / Small Molecule Libraries - chemistry / Small Molecule Libraries - pharmacology / Substrate Specificity / Substrates / Ubiquitin / Ubiquitin-protein ligase / Ubiquitin-Protein Ligases - chemistry / Ubiquitin-Protein Ligases - metabolism / Ubiquitination / Ubiquitination - drug effects / VHL protein / Von Hippel-Lindau Tumor Suppressor Protein - chemistry / Von Hippel-Lindau Tumor Suppressor Protein - metabolism