The nuclear receptor coactivator 3 also known as NCOA3 is a 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...

 that, in humans, is encoded by the NCOA3 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...

. NCOA3 is also frequently called 'amplified in breast 1' (AIB1), steroid receptor coactivator-3 (SRC-3), or thyroid hormone receptor activator molecule 1 (TRAM-1).

Function

NCOA3 is a transcriptional 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 contains several 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...

 interacting domains and an intrinsic histone acetyltransferase

Histone acetyltransferase

Histone acetyltransferases are enzymes that acetylate conserved lysine amino acids on histone proteins by transferring an acetyl group from acetyl CoA to form ε-N-acetyl lysine....

 activity. NCOA3 is recruited to DNA promotion sites by ligand-activated nuclear receptors. NCOA3, in turn, acylates histone

Histone

In biology, histones are highly alkaline proteins found in eukaryotic cell nuclei that package and order the DNA into structural units called nucleosomes. They are the chief protein components of chromatin, acting as spools around which DNA winds, and play a role in gene regulation...

s, which makes downsteam DNA more accessible to transcription. Hence, NCOA3 assists 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...

s in the upregulation of gene expression.

Clinical significance

The ratio of PAX2

PAX2

Paired box gene 2, also known as PAX2 is a protein which in humans is encoded by the PAX2 gene.-Function:PAX2 encodes paired box gene 2, one of many human homologues of the Drosophila melanogaster gene prd. The central feature of this transcription factor gene family is the conserved DNA-binding...

 to AIB-1 protein expression may be predictive of the effectiveness of tamoxifen

Tamoxifen

Tamoxifen is an antagonist of the estrogen receptor in breast tissue via its active metabolite, hydroxytamoxifen. In other tissues such as the endometrium, it behaves as an agonist, hence tamoxifen may be characterized as a mixed agonist/antagonist...

 in breast cancer treatment

Breast cancer treatment

The mainstay of breast cancer treatment is surgery when the tumor is localized, followed by chemotherapy , radiotherapy and adjuvant hormonal therapy for ER positive tumours . Management of breast cancer is undertaken by a multidisciplinary team based on national and international guidelines...

.

Interactions

Nuclear receptor coactivator 3 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 DDX17

DDX17

Probable ATP-dependent RNA helicase DDX17 is an enzyme that in humans is encoded by the DDX17 gene.-Interactions:DDX17 has been shown to interact with HDAC1, Nuclear receptor coactivator 1, Nuclear receptor coactivator 3, Estrogen receptor alpha, Nuclear receptor coactivator 2, SRA1,, DDX5 and...

, IKK2

IKK2

IKK-β also known as inhibitor of nuclear factor kappa-B kinase subunit beta is a protein that in humans is encoded by the IKBKB gene.- Function :...

, Androgen receptor

Androgen receptor

The androgen receptor , also known as NR3C4 , is a type of nuclear receptor that is activated by binding of either of the androgenic hormones testosterone or dihydrotestosterone in the cytoplasm and then translocating into the nucleus...

, CREB-binding protein, Glucocorticoid receptor

Glucocorticoid receptor

The glucocorticoid receptor also known as NR3C1 is the receptor to which cortisol and other glucocorticoids bind....

, Peroxisome proliferator-activated receptor gamma

Peroxisome proliferator-activated receptor gamma

Peroxisome proliferator-activated receptor gamma , also known as the glitazone receptor, or NR1C3 is a type II nuclear receptor that in humans is encoded by the PPARG gene.Two isoforms of PPARG are detected in the human and in the mouse: PPAR-γ1 and...

, IKBKG

IKBKG

NF-kappa-B essential modulator also known as inhibitor of nuclear factor kappa-B kinase subunit gamma is a protein that in humans is encoded by the IKBKG gene. NEMO is a subunit of the IκB kinase that activates NF-κB. The human gene for IKBKG is located on chromosome Xq28...

, Estrogen receptor alpha

Estrogen receptor alpha

Estrogen receptor alpha , also known as NR3A1 , is a nuclear receptor that is activated by the sex hormone estrogen...

, Estrogen receptor beta

Estrogen receptor beta

Estrogen receptor beta , also known as NR3A2 , is a nuclear receptor which is activated by the sex hormone estrogen. In humans, ER-β is encoded by the ESR2 gene.- Function :...

, DDX5

DDX5

Probable ATP-dependent RNA helicase DDX5 also known as DEAD box protein 5 or RNA helicase p68 is an enzyme that in humans is encoded by the DDX5 gene.- Function :...

, CHUK

CHUK

Inhibitor of nuclear factor kappa-B kinase subunit alpha also known as IKK1 or conserved helix-loop-helix ubiquitous kinase is a protein kinase that in humans is encoded by the CHUK gene. IKK-α is part of the IκB kinase complex that plays an important role in regulating the NF-κB transcription...

 and Retinoid X receptor alpha

Retinoid X receptor alpha

Retinoid X receptor alpha , also known as NR2B1 is a nuclear receptor that in humans is encoded by the RXRA gene.- Function :...

.

Further reading