Small heterodimer partner
Encyclopedia
The small heterodimer partner (SHP) also known as NR0B2 (nuclear receptor subfamily 0, group B, member 2) 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 NR0B2 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...

. SHP is a member of 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 of intracellular
Intracellular
Not to be confused with intercellular, meaning "between cells".In cell biology, molecular biology and related fields, the word intracellular means "inside the cell".It is used in contrast to extracellular...

 transcription factor
Transcription factor
In molecular biology and genetics, a transcription factor is a protein that binds to specific DNA sequences, thereby controlling the flow of genetic information from DNA to mRNA...

s. SHP is unusual for a nuclear receptor in that it lacks a DNA binding domain. Therefore technically it is neither a transcription factor nor nuclear receptor but nevertheless it is still classified as such due to relatively high sequence homology with other nuclear receptor family members.

Function

The principle role of SHP appears to be repression of other nuclear receptors through association to produce a non-productive heterodimer. The protein has been shown to interact with retinoid
Retinoid receptor
Retinoid receptors are nuclear receptors that bind to retinoids. When bound to a retinoid, they act as transcription factors, altering the expression of genes with corresponding response elements.Subtypes include:...

 and thyroid hormone receptor
Thyroid hormone receptor
The thyroid hormone receptor is a type of nuclear receptor that is activated by binding thyroid hormone.-Function:Amongst the most important functions of thyroid hormone receptors are regulation of metabolism and heart rate...

s, inhibiting their ligand-dependent transcriptional activation. In addition, interaction with estrogen receptors has been demonstrated, leading to inhibition of function. Studies suggest that the protein represses nuclear hormone receptor-mediated transactivation via two separate steps: competition with coactivators and the direct effects of its transcriptional repressor function.

Interactions

Small heterodimer partner 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:
  • 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...

    ,
  • 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...

    ,
  • Hepatocyte nuclear factor 4 alpha
    Hepatocyte nuclear factor 4 alpha
    Hepatocyte nuclear factor 4 alpha also known as NR2A1 is a nuclear receptor that in humans is encoded by the HNF4A gene.- Function :...

    ,
  • Liver receptor homolog-1
    Liver receptor homolog-1
    The liver receptor homolog-1 also known as NR5A2 is a protein that in humans is encoded by the NR5A2 gene...

    ,
  • Liver X receptor alpha
    Liver X receptor alpha
    Liver X receptor alpha is a nuclear receptor protein that in humans is encoded by the NR1H3 gene .- Expression :...

    ,
  • 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...

    ,
  • Retinoic acid receptor 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 :...

    , 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 :...

    .
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