NR3C2, also known as Nuclear Receptor Subfamily 3 Group C Member 2 or mineralocorticoid receptor (MR), is a nuclear receptor protein that plays a key role in regulating electrolyte balance and blood pressure. It acts as a ligand-activated transcription factor primarily found in the cytoplasm of target cells. Upon binding to mineralocorticoid hormones like aldosterone, NR3C2 undergoes a conformational change and moves into the nucleus to mediate its effects. Its main function includes regulating sodium and potassium ion transport in the kidney, colon, and salivary glands.