Proximity Assays

Molecular glue degraders (MGDs) are small molecules that degrade proteins of interest via the ubiquitin−proteasome system. While
MGDs were historically discovered serendipitously, approaches for MGD discovery now include cell-viability-based drug screens or data mining of public transcriptomics and drug response datasets. These approaches, however, have target spaces restricted to the essential proteins. Here we develop a high-throughput workflow for MGD discovery that also reaches the nonessential proteome. This workflow begins with the rapid synthesis of a compound library by sulfur(VI) fluoride exchange chemistry coupled to a morphological profiling assay in isogenic cell lines that
vary in levels of the E3 ligase CRBN. By comparing the morphological changes induced by compound treatment across the isogenic
cell lines, we were able to identify FL2-14 as a CRBN-dependent MGD targeting the nonessential protein GSPT2. We envision that
this workflow would contribute to the discovery and characterization of MGDs that target a wider range of proteins.