Figure 3.

The structural domains of nuclear receptors (NRs). Sites within NRs are typically classified into six regions (called regions A–F), which correspond to five structural domains. The A/B region contains activation function 1, and corresponds to the N-terminal domain (NTD) of the protein. Region C is the highly conserved DNA binding domain (DBD). Region D is a flexible hinge region that connects the DBD to region E. Region E corresponds to the ligand binding domain (LBD) and contains activation function 2. The C-terminal domain (CTD, region F) varies in length between the different NRs and is nonexistent in some NRs.