Oligomeric Remodeling by Molecular Glues Revealed Using Native Mass Spectrometry and Mass Photometry

Molecular glues stabilize interactions between E3 ligasesand novelsubstrates to promote substrate degradation, thereby facilitatingthe inhibition of traditionally undruggable proteintargets. However, most known molecular glues have been discoveredfortuitously or are based on well-established chemical scaffolds.Efficient approaches for discovering and characterizing the effectsof molecular glues on protein interactions are required to acceleratethe discovery of novel agents. Here, we demonstrate that native massspectrometry and mass photometry can provide unique insights intothe physical mechanism of molecular glues, revealing previously unknowneffects of such small molecules on the oligomeric organization ofE3 ligases. When compared to well-established solution phase assays,native mass spectrometry provides accurate quantitative descriptionsof molecular glue potency and efficacy while also enabling the bindingspecificity of E3 ligases to be determined in a single, rapid measurement.Such mechanistic insights should accelerate the rational developmentof molecular glues to afford powerful therapeutic agents.

Automated summary

Molecular glues stabilize interactions between E3 ligases and novel substrates to promote substrate degradation, facilitating the inhibition of traditionally undruggable protein targets. Efficient approaches for discovering and characterizing the effects of molecular glues on protein interactions are required to accelerate the discovery of novel agents.