Rational discovery of molecular glues for the glucocorticoid receptor – 14-3-3 protein-protein interaction starting with application of traditional hit-finding methods

Given the importance of glucocorticoid receptor (GR) agonists in medicine, despite their numerous adverse side effects, it is of great interest to fully delineate the regulatory network of GR. Post-translational modifications form part of this regulatory network including phosphorylation. After phosphorylation GR interacts with 14-3-3, adding another layer of regulation beyond the ligand-driven activation. Here, we use a screening strategy inspired from traditional hit-finding methods for prospective identification of the first de novo molecular glues of the GR–14-3-3 protein-protein interactions (PPI). Screening 8,000 compounds led to the discovery of one hit. To foster confidence in its stabilisation activity, this hit was further investigated in an array of experiments using biophysical assays, 1D and 2D NMR spectroscopy, and analysis of near neighbours outlined initial structure activity relationships. In addition, those early chemical probes provide starting points for future development into potent tool compounds which could contribute to answer the long-standing question of the physiological role of the GR–14-3-3 PPI.