The multimerization pathway of the glucocorticoid receptor

The glucocorticoid receptor (GR) is a leading drug target due to its anti-inflammatory and immunosuppressive roles. The functional oligomeric conformation of full-length GR (FL-GR), which is key for its biological activity, remains disputed. Here we present a new crystal structure of agonist-bound GR ligand-binding domain (GR-LBD) comprising eight copies of a non-canonical dimer. The biological relevance of this dimer for receptor multimerization in living cells has been verified by studying single-and double-point mutants of FL-GR in fluorescence microscopy (Number & Brightness) and transcriptomic analysis. Self-association of this GR-LBD basic dimer in two mutually exclusive assemblies reveals clues for FL-GR multimerization and activity in cells. We propose a model for the structure of multidomain GR based on our new data and suggest a detailed oligomerization pathway. This model reconciles all currently available structural and functional information and provides a more comprehensive understanding of the rare glucocorticoid resistance disorder (Chrousos syndrome).