Mineralocorticoid Receptor

The mineralocorticoid receptor (MR), encoded by the NR3C2 gene, is a ligand activated transcription factor that belongs to the nuclear receptor superfamily. The MR mediates the physiological action of aldosterone, and cortisol, which both have important roles in the maintenance of homeostasis. MR is essential for blood pressure regulation and electrolyte and fluid homeostasis. The structure of MR consists of an N-terminal A/B domain (NTD), responsible for cofactor, the highly conserved DNA-binding domain (DBD), with a high homology to the GR, and after a short relatively poorly conserved hinge region comes the C-terminal ligand-binding domain (LBD). The NTD regulates transactivation (mainly by region activation function 1, AF-1) but also interacts with the LBD in an N-C interaction that stabilizes the receptor conformation. The DBD binds to the hormone response element (HRE) of MR-regulated genes to mediate transcription.12 The MR LBD is very conserved between species and has multiple functions, that includes, besides ligand binding, also nuclear localization, dimerization, interaction with chaperones, and modulation of transcriptional coactivators and ligand-dependent transactivation.