Mineralocorticoid receptor

The mineralocorticoid receptor (or MR, MLR, MCR), also known as the aldosterone receptor or nuclear receptor subfamily 3, group C, member 2, (NR3C2) is a protein that in humans is encoded by the NR3C2 gene that is located on chromosome 4q31.1-31.2.

MR is a receptor with high affinity for mineralocorticoids. It belongs to the nuclear receptor family where the ligand diffuses into cells, interacts with the receptor and results in a signal transduction affecting specific gene expression in the nucleus.

Function

MR is expressed in many tissues, such as the kidney, colon, heart, central nervous system (hippocampus), brown adipose tissue and sweat glands. In epithelial tissues, its activation leads to the expression of proteins regulating ionic and water transports (mainly the epithelial sodium channel or ENaC, Na+/K+ pump, serum and glucocorticoid induced kinase or SGK1) resulting in the reabsoprtion of sodium, and as a consequence an increase in extracellular volume, increase in blood pressure, and an excretion of potassium to maintain a normal salt concentration in the body.

The receptor is activated by mineralocorticoids such as aldosterone and deoxycorticosterone as well as glucocorticoids, like cortisol. In intact animals, the mineralocorticoid receptor is "protected" from glucocorticoids by co-localization of an enzyme, 11ß-hydroxysteroid dehydrogenase type 2 (11ß-HSD2), that converts cortisol to inactive...
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