Mineralocorticoid Receptor

The mineralocorticoid receptor (MR), encoded by the NR3C2 gene, is a nuclear receptor that functions as a ligand-activated transcription factor. It plays a critical role in regulating sodium and water balance, blood pressure, and electrolyte homeostasis. While aldosterone is the primary physiological ligand, MR also binds glucocorticoids. Tissue-specific expression of 11β-HSD2 ensures aldosterone selectivity in epithelial tissues. Aberrant MR activation is implicated in cardiovascular and metabolic disorders, making it a therapeutic target for hypertension and heart failure. Antagonists like spironolactone and eplerenone are used clinically to block excessive mineralocorticoid signaling.

Ligand binding induces receptor translocation to the nucleus, dimerization, binding to hormone response elements on DNA, and recruitment of transcriptional machinery to regulate target gene expression. Antagonists block ligand binding and prevent receptor activation.