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Eicosanoid Receptor
Most of the eicosanoid receptors are integral membrane protein G protein-coupled receptors (GPCRs) that receptor (biochemistry), bind and respond to eicosanoid signaling molecules. Eicosanoids are rapidly metabolized to inactive products and therefore are short-lived. Accordingly, the eicosanoid-receptor interaction is typically limited to a local interaction: cells, upon stimulation, metabolize arachidonic acid to an eicosanoid which then binds cognate receptors on either its parent cell (acting as an autocrine signalling molecule) or on nearby cells (acting as a paracrine signalling molecule) to trigger functional responses within a restricted tissue area, e.g. an inflammatory response to an invading pathogen. In some cases, however, the synthesized eicosanoid travels through the blood (acting as a hormone-like messenger) to trigger systemic or coordinated tissue responses, e.g. prostaglandin (PG) E2 released locally travels to the hypothalamus to trigger a febrile reaction (see ) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integral Membrane Protein
An integral, or intrinsic, membrane protein (IMP) is a type of membrane protein that is permanently attached to the biological membrane. All transmembrane proteins can be classified as IMPs, but not all IMPs are transmembrane proteins. IMPs comprise a significant fraction of the proteins encoded in an organism's genome. Proteins that cross the membrane are surrounded by annular lipids, which are defined as lipids that are in direct contact with a membrane protein. Such proteins can only be separated from the membranes by using detergents, nonpolar solvents, or sometimes denaturing agents. Proteins that adhere only temporarily to cellular membranes are known as peripheral membrane proteins. These proteins can either associate with integral membrane proteins, or independently insert in the lipid bilayer in several ways. Structure Three-dimensional structures of ~160 different integral membrane proteins have been determined at atomic resolution by X-ray crystallography or nucle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BLT2
Leukotriene B4 receptor 2, also known as BLT2, BLT2 receptor, and BLTR2, is an Integral membrane protein that is encoded by the LTB4R2 gene in humans and the Ltbr2 gene in mice. Discovered several years after the leukotriene B4 receptor 1 (BLT1), BLT2 receptor binds leukotriene B4 (LTB4) with far lower affinity than the BLT1 receptor does and therefore has been termed the low affinity LTB4 receptor. Sometime after its initial discovery, the BLT2 receptor was shown to bind and become activated by several other arachidonic acid metabolites, one of which, 12-hydroxyheptadecatrienoic acid (12-HHT), has 10- to 100-fold higher affinity for it than does LTB4; 12-HHT fails to bind or activate BLT1 receptors. While BLT2 receptors have some actions similar to BLT1 receptors, they have other actions which clearly oppose those of BLT1 in regulating inflammation and allergic responses; BLT2 receptors also have actions that extend beyond those of BLT1 receptors. Laboratory, animal, and ot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Nervous System
The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all parts of the bodies of bilateria, bilaterally symmetric and triploblastic animals—that is, all multicellular animals except sponges and Coelenterata, diploblasts. It is a structure composed of nervous tissue positioned along the Anatomical_terms_of_location#Rostral,_cranial,_and_caudal, rostral (nose end) to caudal (tail end) axis of the body and may have an enlarged section at the rostral end which is a brain. Only arthropods, cephalopods and vertebrates have a true brain, though precursor structures exist in onychophorans, gastropods and lancelets. The rest of this article exclusively discusses the vertebrate central nervous system, which is radically distinct from all other animals. Overview In vertebrates, the brain and spinal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leukotriene E4
Leukotriene E4 (LTE4) is a cysteinyl leukotriene involved in inflammation. It is known to be produced by several types of white blood cells, including eosinophils, mast cells, tissue macrophages, and basophils, and recently was also found to be produced by platelets adhering to neutrophils. It is formed from the sequential conversion of LTC4 to LTD4 and then to LTE4, which is the final and most stable cysteinyl leukotriene. Compared to the short half lives of LTC4 and LTD4, LTE4 is relatively stable and accumulates in breath condensation, in plasma, and in urine, making it the dominant cysteinyl leukotriene detected in biologic fluids. Therefore, measurements of LTE4, especially in the urine, are commonly monitored in clinical research studies. Increased production and excretion of LTE4 has been linked to several respiratory diseases, and urinary LTE4 levels are increased during severe asthma attacks and are especially high in people with aspirin-exacerbated respiratory disea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leukotriene D4
Leukotriene D4 (LTD4) is one of the leukotrienes. Its main function in the body is to induce the contraction of smooth muscle, resulting in bronchoconstriction and vasoconstriction. It also increases vascular permeability. LTD4 is released by basophils. Other leukotrienes that function in a similar manner are leukotrienes C4 and E4. Pharmacological agents that inhibit the function of these leukotrienes are leukotriene receptor antagonists (e.g., zafirlukast, montelukast) and are useful for asthmatic individuals. References Eicosanoids {{biochemistry-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leukotriene C4
Leukotriene C4 (LTC4) is a leukotriene. LTC4 has been extensively studied in the context of allergy and asthma. In cells of myeloid origin such as mast cells, its biosynthesis is orchestrated by translocation to the nuclear envelope along with co-localization of PLA2G4A, cytosolic phospholipase A2 (cPLA2), 5-lipoxygenase, arachidonate 5-lipoxygenase (5-LO), 5-lipoxygenase-activating protein (FLAP) and Leukotriene C4 synthase, LTC4 synthase (LTC4S), which couples glutathione to an Leukotriene A4, LTA4 intermediate. The ABCC1, MRP1 transporter then secretes cytosolic LTC4 and cell surface proteases further metabolize it by sequential cleavage of the γ-glutamyl and glycine residues off its glutathione segment, generating the more stable products Leukotriene D4, LTD4 and Leukotriene E4, LTE4. All three leukotrienes then bind at different affinities to two G-protein coupled receptors: CYSLTR1 and CYSLTR2, triggering pulmonary vasoconstriction and bronchoconstriction. In cells of non-h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GPR17
Uracil nucleotide/cysteinyl leukotriene receptor is a G protein-coupled receptor that in humans is encoded by the ''GPR17'' gene located on chromosome 2 at position q21. The actual activating ligands for and some functions of this receptor are disputed. History Initially discovered in 1998 as an Orphan receptor, i.e. a receptor whose activating ligand(s) and function were unknown, GPR17 was "deorphanized" in a study that reported it to be a receptor for LTC4, LTD4, and uracil nucleotides. In consequence, GPR17 attracted attention as a potential mediator of reactions caused by LTC4 and LTD4 viz., asthma, rhinitis, and urticarial triggered by allergens, nonsteroidal anti-inflammatory drugs, and exercise (see Aspirin-induced asthma). Subsequent reports, however, have varied in results: studies focusing on the allergen and non-allergen reactions find that GPR17-bearing cells do not respond to LTC4, LTD4, and uracil nucleotides while studies focusing on nerve tissue find that certain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leukotriene E4
Leukotriene E4 (LTE4) is a cysteinyl leukotriene involved in inflammation. It is known to be produced by several types of white blood cells, including eosinophils, mast cells, tissue macrophages, and basophils, and recently was also found to be produced by platelets adhering to neutrophils. It is formed from the sequential conversion of LTC4 to LTD4 and then to LTE4, which is the final and most stable cysteinyl leukotriene. Compared to the short half lives of LTC4 and LTD4, LTE4 is relatively stable and accumulates in breath condensation, in plasma, and in urine, making it the dominant cysteinyl leukotriene detected in biologic fluids. Therefore, measurements of LTE4, especially in the urine, are commonly monitored in clinical research studies. Increased production and excretion of LTE4 has been linked to several respiratory diseases, and urinary LTE4 levels are increased during severe asthma attacks and are especially high in people with aspirin-exacerbated respiratory disea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GPR99
OXGR1, i.e., 2-oxoglutarate receptor 1 (also known as GPR99, cysteinyl leukotriene receptor E, i.e., CysLTE, and cysteinyl leukotriene receptor 3, i.e., CysLT3) is a G protein-coupled receptor located on the cell surface membrane, surface membranes of certain cells. It functions by binding one of its Ligand (biochemistry), ligands and thereby becoming active in triggering pre-programmed responses in its parent cells. OXGR1 has been shown to be activated by α-ketoglutarate, itaconate, and three Cysteine, cysteinyl-containing leukotrienes (abbreviated as CysLTs), leukotriene E4 (i.e., LTE4), LTC4, and LTD4. α-Ketoglutarate and itaconate are the dianionic forms of alpha-ketoglutaric acid, α-ketoglutaric acid and itaconic acid, respectively. α-Ketoglutaric and itaconic acids are short-chain dicarboxylic acids that have two carboxyl groups (notated as -) both of which are bound to hydrogen (i.e., ). However, at the Base (chemistry), basic pH levels (i.e., pH>7) in virtually all anima ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cysteinyl Leukotriene Receptor 2
Cysteinyl leukotriene receptor 2, also termed CYSLTR2, is a receptor for cysteinyl leukotrienes (LT) (see leukotrienes#Cysteinyl leukotrienes). CYSLTR2, by binding these cysteinyl LTs (CysLTs; viz, LTC4, LTD4, and to a much lesser extent, LTE4) contributes to mediating various allergic and hypersensitivity reactions in humans. However, the first discovered receptor for these CsLTs, cysteinyl leukotriene receptor 1 (CysLTR1), appears to play the major role in mediating these reactions. Gene The human gene maps to the long arm of chromosome 13 at position 13q14, a chromosomal region that has long been linked to asthma and other allergic diseases. The gene consists of four exons with all introns located in the genes' 5' UTR region and the entire coding region located in the last exon. CysLTR2'' encodes a protein composed of 347 amino acids and shows only modest similarity to the ''CysLTR1'' gene in that its protein shares only 31% amino acid identity with the CysLTR1 protein. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leukotriene D4
Leukotriene D4 (LTD4) is one of the leukotrienes. Its main function in the body is to induce the contraction of smooth muscle, resulting in bronchoconstriction and vasoconstriction. It also increases vascular permeability. LTD4 is released by basophils. Other leukotrienes that function in a similar manner are leukotrienes C4 and E4. Pharmacological agents that inhibit the function of these leukotrienes are leukotriene receptor antagonists (e.g., zafirlukast, montelukast) and are useful for asthmatic individuals. References Eicosanoids {{biochemistry-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
