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

Gene

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

 that is located on chromosome 4q31.1-31.2.

MR is a receptor with high affinity for mineralocorticoid

Mineralocorticoid

Mineralocorticoids are a class of steroid hormones characterised by their similarity to aldosterone and their influence on salt and water balances.-Physiology:...

s. It belongs to the nuclear receptor

Nuclear receptor

In the field of molecular biology, nuclear receptors are a class of proteins found within cells that are responsible for sensing steroid and thyroid hormones and certain other molecules...

 family where the ligand

Ligand

In coordination chemistry, a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. The bonding between metal and ligand generally involves formal donation of one or more of the ligand's electron pairs. The nature of metal-ligand bonding can range from...

 diffuses into cells, interacts with the receptor and results in a signal transduction

Signal transduction

Signal transduction occurs when an extracellular signaling molecule activates a cell surface receptor. In turn, this receptor alters intracellular molecules creating a response...

 affecting specific gene expression in the nucleus

Cell nucleus

In cell biology, the nucleus is a membrane-enclosed organelle found in eukaryotic cells. It contains most of the cell's genetic material, organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes. The genes within these...

.

Function

MR is expressed in many tissues, such as the kidney

Kidney

The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...

, colon

Colon (anatomy)

The colon is the last part of the digestive system in most vertebrates; it extracts water and salt from solid wastes before they are eliminated from the body, and is the site in which flora-aided fermentation of unabsorbed material occurs. Unlike the small intestine, the colon does not play a...

, heart

Heart

The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...

, central nervous system

Central nervous system

The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...

 (hippocampus

Hippocampus

The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...

), brown adipose tissue

Brown adipose tissue

Brown adipose tissue or brown fat is one of two types of fat or adipose tissue found in mammals....

 and sweat gland

Sweat gland

Sweat glands, or sudoriferous glands, are small tubular structures of the skin that produce sweat. There are two kinds of sweat glands:...

s. In epithelial tissues, its activation leads to the expression of proteins regulating ionic and water transports (mainly the epithelial sodium channel

Epithelial sodium channel

The epithelial sodium channel is a membrane-bound ion-channel that is permeable for Li+-ions, protons and especially Na+-ions. It is a constitutively active ion-channel...

 or ENaC, Na+/K+ pump

Na+/K+-ATPase

Na+/K+-ATPase is an enzyme located in the plasma membrane in all animals.- Sodium-potassium pumps :Active transport is responsible for cells containing relatively high...

, serum and glucocorticoid induced kinase

Serum and glucocorticoid induced kinase

Serum and glucocorticoid induced kinase is a serine/threonine-specific protein kinase which interacts with the mineralocorticoid receptor....

 or SGK1) resulting in the reabsoprtion of sodium

Sodium

Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...

, and as a consequence an increase in extracellular volume, increase in blood pressure, and an excretion of potassium

Potassium

Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...

 to maintain a normal salt concentration in the body.

The receptor is activated by mineralocorticoids such as aldosterone

Aldosterone

Aldosterone is a hormone that increases the reabsorption of sodium ions and water and the release of potassium in the collecting ducts and distal convoluted tubule of the kidneys' functional unit, the nephron. This increases blood volume and, therefore, increases blood pressure. Drugs that...

 and deoxycorticosterone

Deoxycorticosterone

11-Deoxycorticosterone is a steroid hormone produced by the adrenal gland that possesses mineralocorticoid activity and acts as a precursor to aldosterone. As its names indicate, it can be understood as 21-hydroxy- variant of progesterone or a 11-deoxy- variant of corticosterone...

 as well as glucocorticoid

Glucocorticoid

Glucocorticoids are a class of steroid hormones that bind to the glucocorticoid receptor , which is present in almost every vertebrate animal cell...

s, like cortisol

Cortisol

Cortisol is a steroid hormone, more specifically a glucocorticoid, produced by the adrenal gland. It is released in response to stress and a low level of blood glucocorticoids. Its primary functions are to increase blood sugar through gluconeogenesis; suppress the immune system; and aid in fat,...

. 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 cortisone. It also responds to some progestins. Spironolactone

Spironolactone

Spironolactone , commonly referred to as simply spiro, is a diuretic and is used as an antiandrogen.It is a synthetic 17-lactone drug that is a renal competitive aldosterone antagonist in a class of pharmaceuticals called...

 and eplerenone

Eplerenone

Eplerenone is an aldosterone antagonist used as an adjunct in the management of chronic heart failure. It is similar to the diuretic spironolactone, though it may be more specific for the mineralocorticoid receptor and is specifically marketed for reducing cardiovascular risk in patients...

 are mineralocorticoid receptor antagonists

Receptor antagonist

A receptor antagonist is a type of receptor ligand or drug that does not provoke a biological response itself upon binding to a receptor, but blocks or dampens agonist-mediated responses...

.

Activation of the mineralocorticoid receptor, upon the binding of its ligand aldosterone, results in its translocation

Translocation

Translocation may refer to:* Chromosomal translocation, in genetics* Translocation in plants, transport of food or pesticides through phloem or xylem* Protein translocation or protein targeting, a process in protein biosynthesis...

 to the cell nucleus, homodimerization and binding to hormone response element

Hormone response element

A hormone response element is a response element for hormones, a short sequence of DNA within the promoter of a gene that is able to bind a specific hormone receptor complex and therefore regulate transcription...

s present in the promoter of some genes. This results in the complex recruitment of the transcriptional machinery and the transcription

Transcription (genetics)

Transcription is the process of creating a complementary RNA copy of a sequence of DNA. Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language that can be converted back and forth from DNA to RNA by the action of the correct enzymes...

 into mRNA of the DNA

DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 sequence of the activated genes.

Interactions

Mineralocorticoid receptor has been shown to interact

Protein-protein interaction

Protein–protein interactions occur when two or more proteins bind together, often to carry out their biological function. Many of the most important molecular processes in the cell such as DNA replication are carried out by large molecular machines that are built from a large number of protein...

 with:

• Glucocorticoid receptor
  Glucocorticoid receptor
  The glucocorticoid receptor also known as NR3C1 is the receptor to which cortisol and other glucocorticoids bind....
  
   and
• TRIM24
  TRIM24
  Tripartite motif-containing 24 also known as transcriptional intermediary factor 1α is a protein that, in humans, is encoded by the TRIM24 gene.- Function :...
  
  .

External links