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 is_associated_with::gene that is located on chromosome 4q31.1-31.2.

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

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

The receptor is activated by mineralocorticoids such as is_associated_with::aldosterone and its precursor is_associated_with::deoxycorticosterone as well as is_associated_with::glucocorticoids, like is_associated_with::cortisol. In intact animals, the mineralocorticoid receptor is "protected" from glucocorticoids by co-localization of an enzyme, is_associated_with::Corticosteroid 11-beta-dehydrogenase isozyme 2 (aka 11-β-hydroxysteroid dehydrogenase 2; 11ß-HSD2), that converts cortisol to inactive cortisone. It also responds to some is_associated_with::progestins. is_associated_with::Spironolactone and is_associated_with::eplerenone are mineralocorticoid receptor antagonists.

Activation of the mineralocorticoid receptor, upon the binding of its ligand aldosterone, results in its translocation to the cell nucleus, is_associated_with::homodimerization and binding to is_associated_with::hormone response elements present in the promoter of some genes. This results in the complex recruitment of the transcriptional machinery and the transcription into is_associated_with::mRNA of the is_associated_with::DNA sequence of the activated genes.

Interactions
Mineralocorticoid receptor has been shown to interact with:
 * is_associated_with::Glucocorticoid receptor and
 * is_associated_with::TRIM24.