To search for new molecular glue degrader compounds, Mikolaj Slabicki, from the Ebert Lab at the Broad Institute, Dana-Farber Cancer Institute and German Cancer Research Center tested a library of thousands of pre-clinical and clinical compounds for their toxicity in various cancer cell lines. Where the toxicity coincided with a high level of ubiquitin ligase component expression, it was a good indication that this compound was working by a degradation-related mechanism. This led to the identification of a kinase inhibitor called CR8 as a molecular glue degrader of cyclin K, an activator protein of cyclin-dependent kinase 12 (CDK12). Using functional genomics approaches, he identified the other proteins needed for CR8 toxicity, and Zuzanna Kozicka and Georg Petzold from the Thomä lab reconstituted the drug-induced complex in vitro and solved its crystal structure.