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Regulator Of G Protein Signalling
Regulators of G protein signaling (RGS) are protein structural domains or the proteins that contain these domains, that function to activate the GTPase activity of heterotrimeric G-protein α-subunits. RGS proteins are multi-functional, GTPase-accelerating proteins that promote GTP hydrolysis by the α-subunit of heterotrimeric G proteins, thereby inactivating the G protein and rapidly switching off G protein-coupled receptor signaling pathways. Upon activation by receptors, G proteins exchange GDP for GTP, are released from the receptor, and dissociate into a free, active GTP-bound α-subunit and βγ-dimer, both of which activate downstream effectors. The response is terminated upon GTP hydrolysis by the α-subunit (), which can then re-bind the βγ-dimer ( ) and the receptor. RGS proteins markedly reduce the lifespan of GTP-bound α-subunits by stabilising the G protein transition state. Whereas receptors stimulate GTP binding, RGS proteins stimulate GTP hydrolysis. RGS prot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Structural Domain
In molecular biology, a protein domain is a region of a protein's Peptide, polypeptide chain that is self-stabilizing and that Protein folding, folds independently from the rest. Each domain forms a compact folded Protein tertiary structure, three-dimensional structure. Many proteins consist of several domains, and a domain may appear in a variety of different proteins. Molecular evolution uses domains as building blocks and these may be recombined in different arrangements to create proteins with different functions. In general, domains vary in length from between about 50 amino acids up to 250 amino acids in length. The shortest domains, such as zinc fingers, are stabilized by metal ions or Disulfide bond, disulfide bridges. Domains often form functional units, such as the calcium-binding EF-hand, EF hand domain of calmodulin. Because they are independently stable, domains can be "swapped" by genetic engineering between one protein and another to make chimera (protein), chimeric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PH Domain
Pleckstrin homology domain (PH domain) or (PHIP) is a protein domain of approximately 120 amino acids that occurs in a wide range of proteins involved in intracellular signaling or as constituents of the cytoskeleton. This domain can bind phosphatidylinositol lipids within biological membranes (such as phosphatidylinositol (3,4,5)-trisphosphate and phosphatidylinositol (4,5)-bisphosphate), and proteins such as the βγ-subunits of heterotrimeric G proteins, and protein kinase C. Through these interactions, PH domains play a role in recruiting proteins to different membranes, thus targeting them to appropriate cellular compartments or enabling them to interact with other components of the signal transduction pathways. Lipid binding specificity Individual PH domains possess specificities for phosphoinositides phosphorylated at different sites within the inositol ring, e.g., some bind phosphatidylinositol (4,5)-bisphosphate but not phosphatidylinositol (3,4,5)-trisphosphate or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RGS3
Regulator of G-protein signaling 3 is a protein that in humans is encoded by the ''RGS3'' gene. This gene encodes a member of the regulator of G-protein signaling (RGS) family. This protein is a GTP-ase activating protein which inhibits G-protein mediated signal transduction. The protein is largely cytosolic The cytosol, also known as cytoplasmic matrix or groundplasm, is one of the liquids found inside cells ( intracellular fluid (ICF)). It is separated into compartments by membranes. For example, the mitochondrial matrix separates the mitochondri ..., but G-protein activation leads to translocation of this protein to the plasma membrane. A nuclear form of this protein has also been described, but its sequence has not been identified. Multiple alternatively spliced transcript variants have been described for this gene but the full-length nature of some transcripts is not yet known. References Further reading * * * * * * * * * * * * * * * * * * {{gene-9-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RGS2
Regulator of G-protein signaling 2 is a protein that in humans is encoded by the ''RGS2'' gene. It is part of a larger family of RGS proteins that control signalling through G-protein coupled receptors (GPCR). Function RGS2 is thought to have protective effects against myocardial hypertrophy as well as atrial arrhythmias. Increased stimulation of Gs coupled β1-adrenergic receptors and Gq coupled α1-adrenergic receptors in the heart can result in cardiac hypertrophy. In the case of Gq protein coupled receptor (GqPCR) mediated hypertrophy, Gαq will activate the intracellular affectors phospholipase Cβ and rho guanine nucleotide exchange factor to stimulate cell processes which lead to cardiomyocyte hypertrophy. RGS2 functions as a GTPase Activating Protein (GAP) which acts to increase the natural GTPase activity of the Gα subunit. By increasing the GTPase activity of the Gα subunit, RGS2 promotes GTP hydrolysis back to GDP, thus converting the Gα subunit back to its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RGS1
Regulator of G-protein signaling 1 is a protein that in humans is encoded by the ''RGS1'' gene. This gene encodes a member of the regulator of G-protein signaling family. This protein is located on the cytosolic side of the plasma membrane and contains a conserved, 120 amino acid motif called the RGS domain. The protein attenuates the signalling activity of G-proteins by binding to activated, GTP-bound G alpha subunits and acting as a GTPase activating protein (GAP), increasing the rate of conversion of the GTP to GDP. This hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water ... allows the G alpha subunits to bind G beta/gamma subunit heterodimers, forming inactive G-protein heterotrimers, thereby terminating the signal. References Further reading * * * * * * * * * * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G Protein-coupled Receptor Kinase 7
G-protein-coupled receptor kinase 7 (, ''GRK7'', ''cone opsin kinase'', ''iodopsin kinase'') is a serine/threonine-specific protein kinase involved in phototransduction Visual phototransduction is the sensory transduction process of the visual system by which light is detected by photoreceptor cells ( rods and cones) in the vertebrate retina. A photon is absorbed by a retinal chromophore (each bound to an opsin), .... This enzyme catalyses the phosphorylation of cone (color) photopsins in retinal cones during high acuity color vision primarily in the fovea. More on GRK7 GRK7 is a member of the family of G protein-coupled receptor kinases, and is officially named G protein-coupled receptor kinase 7. GRK7 is found primarily in mammalian retinal cone cells, where it phosphorylates light-activated photopsins, members of the family of G protein-coupled receptors that recognize light of various wavelengths (red, green, blue). Phosphorylated, light-activated photopsin binds to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GRK6
This gene encodes a member of the G protein-coupled receptor kinase subfamily of the Ser/Thr protein kinase family, and is most highly similar to GRK4 and GRK5. The protein phosphorylates the activated forms of G protein-coupled receptors to regulate their signaling. Function G protein-coupled receptor kinases phosphorylate activated G protein-coupled receptors, which promotes the binding of an arrestin protein to the receptor. Arrestin binding to phosphorylated, active receptor prevents receptor stimulation of heterotrimeric G protein transducer proteins, blocking their cellular signaling and resulting in receptor desensitization. Arrestin binding also directs receptors to specific cellular internalization pathways, removing the receptors from the cell surface and also preventing additional activation. Arrestin binding to phosphorylated, active receptor also enables receptor signaling through arrestin partner proteins. Thus the GRK/arrestin system serves as a complex signal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GRK5
G protein-coupled receptor kinase 5 is a member of the G protein-coupled receptor kinase subfamily of the Ser/Thr protein kinases, and is most highly similar to GRK4 and GRK6. The protein phosphorylates the activated forms of G protein-coupled receptors to regulate their signaling. Function G protein-coupled receptor kinases phosphorylate activated G protein-coupled receptors, which promotes the binding of an arrestin protein to the receptor. Arrestin binding to phosphorylated, active receptor prevents receptor stimulation of heterotrimeric G protein transducer proteins, blocking their cellular signaling and resulting in receptor desensitization. Arrestin binding also directs receptors to specific cellular internalization pathways, removing the receptors from the cell surface and also preventing additional activation. Arrestin binding to phosphorylated, active receptor also enables receptor signaling through arrestin partner proteins. Thus the GRK/arrestin system serves as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GRK4
G protein-coupled receptor kinase 4 (GRK4) is an enzyme that is encoded by the ''GRK4'' gene in humans. This gene encodes a member of the G protein-coupled receptor kinase subfamily of the Ser/Thr protein kinase family, and is most similar to GRK5 and GRK6. G protein-coupled receptor kinases phosphorylate activated G protein-coupled receptors, which promotes the binding of an arrestin protein to the receptor. Arrestin binding to a phosphorylated, active receptor prevents receptor stimulation of heterotrimeric G protein transducer proteins, blocking their cellular signaling and resulting in receptor desensitization. Moreover Arrestin binding to a phosphorylated, active receptor also enables receptor signaling through arrestin partner proteins. Consequently the GRK/arrestin system serves as a signaling switch for G protein-coupled receptors. GRK4 is most highly expressed in the testes, with lower amounts found in the brain, kidney and other tissues. It exists in four alternati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GRK3
G-protein-coupled receptor kinase 3 (GRK3) is an enzyme that in humans is encoded by the ''ADRBK2'' gene. GRK3 was initially called Beta-adrenergic receptor kinase 2 (βARK-2), and is a member of the G protein-coupled receptor kinase subfamily of the Ser/Thr protein kinases that is most highly similar to GRK2. Function G protein-coupled receptor kinases phosphorylate activated G protein-coupled receptors, which promotes the binding of an arrestin protein to the receptor. Arrestin binding to phosphorylated, active receptor prevents receptor stimulation of heterotrimeric G protein transducer proteins, blocking their cellular signaling and resulting in receptor desensitization. Arrestin binding also directs receptors to specific cellular internalization pathways, removing the receptors from the cell surface and also preventing additional activation. Arrestin binding to phosphorylated, active receptor also enables receptor signaling through arrestin partner proteins. As a resul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GRK2
G-protein-coupled receptor kinase 2 (GRK2) is an enzyme that in humans is encoded by the ''ADRBK1'' gene. GRK2 was initially called Beta-adrenergic receptor kinase (βARK or βARK1), and is a member of the G protein-coupled receptor kinase subfamily of the Ser/Thr protein kinases that is most highly similar to GRK3(βARK2). Functions G protein-coupled receptor kinases phosphorylate activated G protein-coupled receptors, which promotes the binding of an arrestin protein to the receptor. Arrestin binding to phosphorylated, active receptor prevents receptor stimulation of heterotrimeric G protein transducer proteins, blocking their cellular signaling and resulting in receptor desensitization. Arrestin binding also directs receptors to specific cellular internalization pathways, removing the receptors from the cell surface and also preventing additional activation. Arrestin binding to phosphorylated, active receptor also enables receptor signaling through arrestin partner protein ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GRK1
Rhodopsin kinase (, ''rod opsin kinase'', ''G-protein-coupled receptor kinase 1'', ''GPCR kinase 1'', ''GRK1'', ''opsin kinase'', ''opsin kinase (phosphorylating)'', ''rhodopsin kinase (phosphorylating)'', ''RK'', ''STK14'') is a serine/threonine-specific protein kinase involved in phototransduction. This enzyme catalyses the following chemical reaction: : ATP + rhodopsin \rightleftharpoons ADP + phospho-rhodopsin Mutations in rhodopsin kinase are associated with a form of night blindness called Oguchi disease. Function and mechanism of action Rhodopsin kinase is a member of the family of G protein-coupled receptor kinases, and is officially named G protein-coupled receptor kinase 1, or GRK1. Rhodopsin kinase is found primarily in mammalian retinal rod cells, where it phosphorylates light-activated rhodopsin, a member of the family of G protein-coupled receptors that recognizes light. Phosphorylated, light-activated rhodopsin binds to the protein arrestin to terminate the lig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
