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Calreticulin
Calreticulin also known as calregulin, CRP55, CaBP3, calsequestrin-like protein, and endoplasmic reticulum resident protein 60 (ERp60) is a protein that in humans is encoded by the ''CALR'' gene. Calreticulin is a multifunctional soluble protein that binds Ca2+ ions (a second messenger in signal transduction), rendering them inactive. The Ca2+ is bound with low affinity, but high capacity, and can be released on a signal (see inositol trisphosphate). Calreticulin is located in storage compartments associated with the endoplasmic reticulum and is considered an ER resident protein. The term "Mobilferrin" is considered to be the same as calreticulin by some sources. Function Calreticulin binds to misfolded proteins and prevents them from being exported from the endoplasmic reticulum to the Golgi apparatus. A similar quality-control molecular chaperone, calnexin, performs the same service for soluble proteins as does calreticulin, however it is a membrane-bound protein. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ERp57
Protein disulfide-isomerase A3 (PDIA3), also known as glucose-regulated protein, 58-kD (GRP58), is an isomerase enzyme encoded by the autosomal gene ''PDIA3'' in humans. This protein localizes to the endoplasmic reticulum (ER) and interacts with lectin chaperones calreticulin and calnexin (CNX) to modulate folding of newly synthesized glycoproteins. It is thought that complexes of lectins and this protein mediate protein folding by promoting formation of disulfide bonds in their glycoprotein substrates. Structure The PDIA3 protein consists of four thioredoxin-like domains: a, b, b′, and a′. The a and a′ domains have Cys-Gly-His-Cys active site motifs (C57-G58-H59-C60 and C406-G407-H408-C409) and are catalytically active. The bb′ domains contain a CNX binding site, which is composed of positively charged, highly conserved residues (K214, K274, and R282) that interact with the negatively charged residues of the CNX P domain. The b′ domain comprises the majority of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calnexin
Calnexin (CNX) is a 67kDa integral protein (that appears variously as a 90kDa, 80kDa, or 75kDa band on western blotting depending on the source of the antibody) of the endoplasmic reticulum (ER). It consists of a large (50 kDa) N-terminal calcium- binding lumenal domain, a single transmembrane helix and a short (90 residues), acidic cytoplasmic tail. In humans, calnexin is encoded by the gene ''CANX''. Function Calnexin is a chaperone, characterized by assisting protein folding and quality control, ensuring that only properly folded and assembled proteins proceed further along the secretory pathway. It specifically acts to retain unfolded or unassembled N-linked glycoproteins in the ER. Calnexin binds only those ''N''-glycoproteins that have GlcNAc2Man9Glc1 oligosaccharides. These monoglucosylated oligosaccharides result from the trimming of two glucose residues by the sequential action of two glucosidases, I and II. Glucosidase II can also remove the third and last glu ... [...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] |
Sjögren Syndrome
Sjögren is a Swedish surname. Notable people with the surname include: * Anders Johan Sjögren (1794–1855), Finnish linguist, historian, ethnographer and explorer * Ann Mari Sjögren, Swedish fantasy artist and illustrator * Christer Sjögren, Swedish dansband and rock singer * Emil Sjögren (1853–1918), Swedish composer * Gunnar A. Sjögren (1920-1996), Swedish engineer who worked for Saab * Henrik Sjögren (1899–1986), Swedish ophthalmologist for whom Sjögren's syndrome was named, an autoimmune disorder leading to dry eyes and mouth * Hjalmar Sjögren, Swedish geologist and mineralogist * John C. Sjogren, United States Army soldier who received the Medal of Honor in World War II * John M. Sjogren American film director * Karin Sjögren (born 1960), Swedish curler, World and European champion * Katrin Sjögren (born 1966), Finnish politician from the Åland Islands * Peder Sjögren (1905–1966), Swedish writer who fought in the Spanish Civil War * Peter Sjögren, Swe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lupus Erythematosus
is a collection of autoimmune diseases in which the human immune system becomes hyperactive and attacks healthy tissues. Symptoms of these diseases can affect many different body systems, including joints, skin, kidneys, blood cells, heart, and lungs. The most common and most severe form is . Signs and symptoms Symptoms vary from person to person, and may come and go. Almost everyone with lupus has joint pain and swelling. Some develop arthritis. Frequently affected joints are the fingers, hands, wrists, and knees. Other common symptoms include: * chest pain during respiration * joint pain (stiffness and swelling) * painless oral ulcer * fatigue * weight loss * headaches * fever with no other cause * Skin lesions that appear worse after sun exposure * general discomfort, uneasiness, or ill feeling (malaise) * hair loss * sensitivity to sunlight * a "butterfly" facial rash, seen in about half of people with SLE * swollen lymph nodes Photosensitivity Photosensitiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antibody
An antibody (Ab) or immunoglobulin (Ig) is a large, Y-shaped protein belonging to the immunoglobulin superfamily which is used by the immune system to identify and neutralize antigens such as pathogenic bacteria, bacteria and viruses, including those that cause disease. Each individual antibody recognizes one or more specific antigens, and antigens of virtually any size and chemical composition can be recognized. Antigen literally means "antibody generator", as it is the presence of an antigen that drives the formation of an antigen-specific antibody. Each of the branching chains comprising the "Y" of an antibody contains a paratope that specifically binds to one particular epitope on an antigen, allowing the two molecules to bind together with precision. Using this mechanism, antibodies can effectively "tag" the antigen (or a microbe or an infected cell bearing such an antigen) for attack by cells of the immune system, or can neutralize it directly (for example, by blocking a p ... [...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] |
Androgen Receptor
The androgen receptor (AR), also known as NR3C4 (nuclear receptor subfamily 3, group C, member 4), is a type of nuclear receptor that is activated by binding any of the androgenic hormones, including testosterone and dihydrotestosterone, in the cytoplasm and then translocating into the Cell nucleus, nucleus. The androgen receptor is most closely related to the progesterone receptor, and progestins in higher dosages can block the androgen receptor. The main function of the androgen receptor is as a DNA-binding protein, DNA-binding transcription factor that Gene expression regulation, regulates gene expression; however, the androgen receptor has other functions as well. Androgen-regulated genes are critical for the development and maintenance of the male sexual phenotype. Function Effect on development In some cell types, testosterone interacts directly with androgen receptors, whereas, in others, testosterone is converted by 5-alpha reductase, 5-alpha-reductase to dihydrot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucocorticoid Response Element
''Response elements'' are short sequences of DNA within a gene promoter or enhancer region that are able to bind specific transcription factors and regulate transcription of genes. Under conditions of stress, a transcription activator protein binds to the response element and stimulates transcription. If the same response element sequence is located in the control regions of different genes, then these genes will be activated by the same stimuli, thus producing a coordinated response. Hormone response element A hormone response element (HRE) is a short sequence of DNA within the promoter of a gene, that is able to bind to a specific hormone receptor complex and therefore regulate transcription. The sequence is most commonly a pair of inverted repeats separated by three nucleotides, which also indicates that the receptor binds as a dimer. Specifically, HRE responds to steroid hormones, as the activated steroid receptor is the transcription factor binding HRE. This regulates the tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucocorticoid Receptor
The glucocorticoid receptor (GR or GCR) also known by its gene name ''NR3C1'' ( nuclear receptor subfamily 3, group C, member 1) is the steroid receptor for glucocorticoids such as cortisol. The GR is expressed in almost every cell in the body and regulates genes controlling the development, metabolism, inflammation, and immune response. Because the receptor gene is expressed in several forms, it has many different ( pleiotropic) effects in different parts of the body and in the context of different diseases. GR is a steroid receptor and thus its canonical action is similar to other steroid receptors. ree full text/ref> The unbound receptor resides in the cytosol of the cell. When glucocorticoids bind to the receptor, GR translocates to the nucleus of the cell where it acts as a transcription factor. The activated GR complex up-regulates the expression of anti-inflammatory proteins in the nucleus or represses the expression of pro-inflammatory proteins in the cytosol (by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-terminus
The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the amine group is bonded to the carboxylic group of another amino acid, making it a chain. That leaves a free carboxylic group at one end of the peptide, called the C-terminus, and a free amine group on the other end called the N-terminus. By convention, peptide sequences are written N-terminus to C-terminus, left to right (in LTR writing systems). This correlates the translation direction to the text direction, because when a protein is translated from messenger RNA, it is created from the N-terminus to the C-terminus, as amino acids are added to the carboxyl end of the protein. Chemistry Each amino acid has an amine group and a carboxylic group. Amino acids link to one another by peptide bonds which form through a dehydration reaction that ... [...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] |
