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Retinoid Receptor
Retinoid receptors are nuclear receptor, type II nuclear receptors (a class of proteins) that bind to retinoids. When bound to a retinoid, they act as transcription factors, altering the gene expression, expression of genes with corresponding response elements. Subtypes include: * Retinoic acid receptors (RARs) * Retinoid X receptors (RXRs) * RAR-related orphan receptors (RORs) References {{DEFAULTSORT:Retinoid Receptor Intracellular receptors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Receptor
In the field of molecular biology, nuclear receptors are a class of proteins responsible for sensing steroids, thyroid hormones, vitamins, and certain other molecules. These intracellular receptors work with other proteins to regulate the expression of specific genes, thereby controlling the development, homeostasis, and metabolism of the organism. Nuclear receptors bind directly to DNA regulating the expression of adjacent genes; hence these receptors are classified as transcription factors. The regulation of gene expression by nuclear receptors often occurs in the presence of a ligand—a molecule that affects the receptor's behavior. Ligand binding to a nuclear receptor results in a conformational change activating the receptor. The result is up- or down-regulation of gene expression. A unique property of nuclear receptors that differentiates them from other classes of receptors is their direct control of genomic DNA. Nuclear receptors play key roles in both embryonic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metabolic reactions, DNA replication, Cell signaling, responding to stimuli, providing Cytoskeleton, structure to cells and Fibrous protein, organisms, and Intracellular transport, transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the Nucleic acid sequence, nucleotide sequence of their genes, and which usually results in protein folding into a specific Protein structure, 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called pep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retinoid
The retinoids are a class of chemical compounds that are natural derivatives of vitamin A or are chemically related to it. Synthetic retinoids are utilized in cosmetic formulations, clinical dermatology, and the treatment of some forms of cancer. Retinoids have many important functions throughout the body, including in vision, regulation of skin proliferation and differentiation, growth of bone tissue, immune function, and male fertility. The biology of retinoids is complex, having well-documented effectiveness in the management of conditions ranging from acute promyelocytic leukemia to acne to photoaging. On the other hand, retinoids may be involved in metabolic dysfunction and, at least in some forms, carcinogenesis. Types Retinoids are divided into four generations based on their molecular structure and receptor selectivity. Structure The basic structure of the hydrophobic retinoid molecule consists of a cyclic end group, a polyene side chain and a polar end group. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transcription Factor
In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription (genetics), transcription of genetics, genetic information from DNA to messenger RNA, by binding to a specific DNA sequence. The function of TFs is to regulate—turn on and off—genes in order to make sure that they are Gene expression, expressed in the desired Cell (biology), cells at the right time and in the right amount throughout the life of the cell and the organism. Groups of TFs function in a coordinated fashion to direct cell division, cell growth, and cell death throughout life; cell migration and organization (body plan) during embryonic development; and intermittently in response to signals from outside the cell, such as a hormone. There are approximately 1600 TFs in the human genome. Transcription factors are members of the proteome as well as regulome. TFs work alone or with other proteins in a complex, by promoting (a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene Expression
Gene expression is the process (including its Regulation of gene expression, regulation) by which information from a gene is used in the synthesis of a functional gene product that enables it to produce end products, proteins or non-coding RNA, and ultimately affect a phenotype. These products are often proteins, but in non-protein-coding genes such as Transfer RNA, transfer RNA (tRNA) and Small nuclear RNA, small nuclear RNA (snRNA), the product is a functional List of RNAs, non-coding RNA. The process of gene expression is used by all known life—eukaryotes (including multicellular organisms), prokaryotes (bacteria and archaea), and viruses—to generate the macromolecule, macromolecular machinery for life. In genetics, gene expression is the most fundamental level at which the genotype gives rise to the phenotype, ''i.e.'' observable trait. The genetic information stored in DNA represents the genotype, whereas the phenotype results from the "interpretation" of that informati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retinoic Acid Receptor
The retinoic acid receptor (RAR) is a type of nuclear receptor which can also act as a ligand-activated transcription factor that is activated by both all-trans retinoic acid and 9-cis retinoic acid, retinoid active derivatives of Vitamin A. They are typically found within the nucleus. There are three retinoic acid receptors (RAR), RAR-alpha, RAR-beta, and RAR-gamma, encoded by the , , genes, respectively. Within each RAR subtype there are various isoforms differing in their N-terminal region A. Multiple splice variants have been identified in human RARs: four for , five for , and two for . 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 known as retinoic acid response elements (RAREs) complexed with corepressor protein. Binding of agonist ligands to RAR results in dissociation of corepressor and recruitment of coactivator protein that, in turn, promotes transcript ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retinoid X Receptor
The retinoid X receptor (RXR) is a type of nuclear receptor that is activated by 9-cis retinoic acid, which is discussed controversially to be of endogenous relevance, and 9-''cis''-13,14-dihydroretinoic acid, which may be an endogenous mammalian RXR-selective agonist. Bexarotene is the only specific activator of the RXRs which does not activate the Retinoic Acid Receptors. There are three retinoic X receptors (RXR): RXR-alpha, RXR-beta, and RXR-gamma, encoded by the , , genes, respectively. RXR heterodimerizes with multiple nuclear receptors including CAR, FXR, LXR, PPAR, PXR, RAR, TR, ER and VDR. RXRs are permissive co-receptors as only one of six alleles is needed for normal development and health. Given this, it is difficult to extrapolate whether the RXR pathway has its own endogenous activity driven by 9-cis retinoic acid species or whether it merely participates in other pathways, predominantly the retinoic nuclear receptor pathway. Genomic knockout of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RAR-related Orphan Receptor
The RAR-related orphan receptors (RORs) are members of the nuclear receptor family of intracellular transcription factors. There are three forms of ROR, ROR-α, -β, and -γ and each is encoded by a separate gene, ''RORA'', ''RORB'', and ''RORC'' respectively. The RORs are somewhat unusual in that they appear to bind as monomers to hormone response elements as opposed to the majority of other nuclear receptors which bind as dimers. They bind to DNA elements called ROR response elements (RORE). Ligands While the identity of natural ligands for the RORs remains controversial, similar to the liver X receptors (LXRs), it appears that the RORs are activated by oxysterols. Furthermore, the RORs appear to be constitutively active (absence of ligand) and that activity may be due to continuously bound natural ligands. Side chain oxygenated sterols (e.g., 20α-hydroxycholesterol, 22R-hydroxycholesterol, and 25-hydroxycholesterol) are high affinity RORγ agonists while sterols ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
