Retinoic acid receptor
Encyclopedia
The retinoic acid receptor (RAR) is a type of nuclear receptor
that is activated by both all-trans retinoic acid
and 9-cis retinoic acid
. There are three retinoic acid receptors (RAR), RAR-alpha
, RAR-beta
, and RAR-gamma
, encoded by the , , genes, respectively. Each receptor isoform has several splice variants: two- for alpha, four- for beta, and two- for gamma.
As with other type II nuclear receptors, RAR heterodimerizes with RXR
and in the absence of ligand, the RAR/RXR dimer binds to hormone response elements complexed with corepressor
protein. Binding of agonist ligand
s to RAR results in dissociation of corepressor and recruitment of coactivator
protein that, in turn, promotes transcription of the downstream target gene
into mRNA and eventually protein
.
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...
that is activated by both all-trans retinoic acid
Retinoic acid
Retinoic acid is a metabolite of vitamin A that mediates the functions of vitamin A required for growth and development. Retinoic acid is required in chordate animals which includes all higher animals from fishes to humans...
and 9-cis retinoic acid
Retinoic acid
Retinoic acid is a metabolite of vitamin A that mediates the functions of vitamin A required for growth and development. Retinoic acid is required in chordate animals which includes all higher animals from fishes to humans...
. There are three retinoic acid receptors (RAR), RAR-alpha
Retinoic acid receptor alpha
Retinoic acid receptor alpha , also known as NR1B1 is a nuclear receptor that in humans is encoded by the RARA gene.- Function :...
, RAR-beta
Retinoic acid receptor beta
Retinoic acid receptor beta , also known as NR1B2 is a nuclear receptor that in humans is encoded by the RARB gene.- Function :...
, and RAR-gamma
Retinoic acid receptor gamma
Retinoic acid receptor gamma , also known as NR1B3 is a nuclear receptor encoded by the RARG gene.- Interactions :...
, encoded by the , , genes, respectively. Each receptor isoform has several splice variants: two- for alpha, four- for beta, and two- for gamma.
As with other type II nuclear receptors, RAR heterodimerizes with RXR
Retinoid X receptor
The retinoid X receptor is a type of nuclear receptor that is activated by 9-cis retinoic acid. There are three retinoic X receptors : RXR-alpha, RXR-beta, and RXR-gamma, encoded by the , , genes, respectively....
and in the absence of ligand, the RAR/RXR dimer binds to hormone response elements complexed with corepressor
Corepressor (genetics)
In molecular genetics, a corepressor is a substance that inhibits the expression of genes. A corepressor downregulates the expression of genes not through direct interaction with a gene promoter , but rather indirectly through interaction with repressor proteins that in turn bind to the...
protein. Binding of agonist 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...
s to RAR results in dissociation of corepressor and recruitment of coactivator
Coactivator (genetics)
A coactivator is a protein that increases gene expression by binding to an activator which contains a DNA binding domain. The coactivator is unable to bind DNA by itself....
protein that, in turn, promotes transcription of the downstream target 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...
into mRNA and eventually protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
.