Abstract: : Purpose: Arrestin rapidly binds both in vivo and in vitro to phosphorylated light-activated rhodopsin (P-Rh*), thereby quenching signaling in rods. However, in vivo arrestin apparently stays in the complex with P-Rh* for a long time, at least until P-Rh* decays into phospho-opsin. To identify the mechanism that slows down arrestin dissociation, we studied it in direct binding assay. Methods: Tritiated arrestin was pre-bound to P-Rh* for 5 min at 37oC, then diluted 50-fold and allowed to dissociate on ice. Aliquots were taken every 15 min. and bound arrestin was measured using gel-filtration-based assay. Results: The half-life of the complex was found to be 123 + 7 min, i.e., extremely long. Our recent mutagenesis data suggest that in the process of arrestin binding to P-Rh* the three-element interaction involving beta-strand I, alpha-helix one, and arrestin C-tail is disrupted. One of the released elements, alpha-helix I (residues 100-111), is a typical amphipathic helix closely ...
Abstract: : Purpose: To elucidate the structural basis for arrestins receptor specificity. Four cloned arrestin proteins participate in homologous desensitization of hundreds of G protein-coupled receptors. Although the receptor specificity of the two non-visual arrestins is not known, the specificity of rod and cone arrestins for their respective pigments is inferred from their selective expression in these two types of photoreceptor cells. Recently we found that cone arrestin has a 50-fold lower affinity for phosphorylated light-activated rhodopsin (P-Rh*) than rod visual arrestin (VA). The difference in affinity of bovine and salamander VA for P-Rh* of the corresponding vs the other species is of similar magnitude. Methods: Experimentally the preference of VA for P-Rh* and that of beta-arrestin (BA) for agonist-activated phosphorylated m2 muscarinic cholinergic receptor (P-m2*) can be measured in the direct binding assay. Each arrestin demonstrates about 6-fold higher binding to the ...
Fuchs S, Nakazawa M, Maw M, Tamai M, Oguchi Y, Gal A. A homozygous 1-base pair deletion in the arrestin gene is a frequent cause of Oguchi disease in Japanese. Nat Genet. 1995 Jul;10(3):360-2.. ...
Target AntigenRetinal S antigen Quantity50ulClonePDS1HostMouse ImmunogenPorcine retinal S-antigen (arrestin)Myeloma/fusion partnersBalb/c Ag 8.653 myeloma cellsSpecies ReactivityRat, Cow, Human, PigPurificationProtein GFormatPurified antibody (from supernatant) containing PBS 0.1% sodium azideApplicationsWB, IHC-Fr, IC
Arrestins are ubiquitous adaptor proteins that are implicated in diverse signaling pathways. Arrestins are involved in the regulation of G-protein coupled receptors (GPCRs) via endocytosis and desensitization followed by degradation or recycling of the receptor. There are two β-arrestin homologs in mammals, which are largely redundant and therefore difficult to study. Drosophila has a single β-arrestin, Kurtz (Krz), and hence presents unique opportunities to study the functions of β-arrestin. krz maternal mutants have been shown to cause defects in the gastrulation of Drosophila embryos. These were attributed to effects of Krz on Toll signaling pathway. To investigate the origins of the defects, the early hours of embryo development needed to be examined. One of the main pathways activated during the first hours of gastrulation that enables epithelial remodeling and ventral furrow formation is Fog-Mist signaling. Mist is a GPCR that is activated by Fog, which triggers a cascade of downstream
CCR2 is a well studied chemokine receptor that meets considerable clinical interest. Yet, few studies have been investigating recruitment of β-arrestin to CCR2, with CCL2 as the sole analyzed CCR2 ligand (Aragay et al., 1998; García Lopez et al., 2009). Thus, we report the first study dedicated to the investigation of the effects of different CCR2 ligands on β-arrestin recruitment. We demonstrate that the effects of different CCR2 ligands on β-arrestin recruitment to the receptor are quantitatively and qualitatively distinct from one another. Differences were found in recruitment efficacy, identifying CCL7, CCL8, and CCL13 as partial agonists, with submaximal responses despite full receptor occupancy. Comparing β-arrestin 1 or 2, we found potential bias toward β-arrestin 2 of CCL13 and CCL8, overall weak β-arrestin recruiters. Experiments addressing the decline of the CCR2/β-arrestin interaction over time revealed striking differences between the ligands. Although CCL7-induced ...
G protein-coupled receptors are a large family of signalling molecules that respond to a wide variety of extracellular stimuli. The receptors relay the information encoded by the ligand through the activation of heterotrimeric G proteins and intracellular effector molecules. To ensure the appropriate regulation of the signalling cascade, it is vital to properly inactivate the receptor. This inactivation is achieved, in part, by the binding of a soluble protein, arrestin, which uncouples the receptor from the downstream G protein after the receptors are phosphorylated by G protein-coupled receptor kinases. In addition to the inactivation of G protein-coupled receptors, arrestins have also been implicated in the endocytosis of receptors and cross talk with other signalling pathways. Arrestin (retinal S-antigen) is a major protein of the retinal rod outer segments. It interacts with photo-activated phosphorylated rhodopsin, inhibiting or arresting its ability to interact with transducin ...
Idiopathic pulmonary fibrosis is a progressive disease that causes unremitting extracellular matrix deposition with resulting distortion of pulmonary architecture and impaired gas exchange. β-Arrestins regulate G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptors through receptor desensitization while also acting as signaling scaffolds to facilitate numerous effector pathways. Here, we examine the role of β-arrestin1 and β-arrestin2 in the pathobiology of pulmonary fibrosis. In the bleomycin-induced mouse lung fibrosis model, loss of either β-arrestin1 or β-arrestin2 resulted in protection from mortality, inhibition of matrix deposition, and protected lung function. Fibrosis was prevented despite preserved recruitment of inflammatory cells and fibroblast chemotaxis. However, isolated lung fibroblasts from bleomycin-treated β-arrestin-null mice failed to invade extracellular matrix and displayed altered expression of genes involved in matrix production and ...
β-arrestin2 is well known to function as a scaffold for some MAP kinase modules thereby contributing to the activation of mitogen-activated protein kinases by GPCRs. We investigated activation of MAPKs in spermatozoa upon bourgeonal treatment and found that activation of hOR17-4 leads to phosphorylation of ERK1/2 and p38 MAPK. Interestingly, activated ERK1/2 showed nuclear localization. MAPK activation by GPCR-bound arrestin is generally thought to target the MAPK to specific extranuclear locations (Luttrell, 2003; Lefkowitz and Shenoy, 2005). In spite of this, it was recently shown that β-arrestin2 promotes a subset of ERK1/2-mediated transcriptional responses to lysophosphatidic acid receptor activation (Gesty-Palmer et al., 2005) and β2-adrenergic receptor-mediated nuclear translocation of ERK (Kobayashi et al., 2005). Whether the observed nuclear translocation of β-arrestin2 upon hOR17-4 activation in spermatozoa causes the nuclear translocation of ERK1/2, as in the cases of activated ...
Arrestins play a fundamental role in the regulation and signal transduction of G protein-coupled receptors. Here we describe the crystal structure of cone arrestin at 2.3A resolution. The overall structure of cone visual arrestin is similar to the crystal structures of rod visual and the non-visual …
cAMP is a well studied second messenger that is ubiquitously expressed in mammals. It conducts its function by activating its downstream effectors: protein kinase A (PKA), exchange proteins regulated by cAMP (EPAC) and cyclic nucleotide gated ion-channels. The sole mechanism to inactivate cAMP is through degradation via cyclic-phosphodiesterases (PDEs). The PDEs, especially PDE4s, are involved in many diseases including asthma, chronic obstructive pulmonary disease (COPD) and depression. Therefore, PDEs have been a consistently popular research subject for decades and pharmaceutical companies have devoted considerable effort in developing PDE inhibitors. β-arrestin interacts with PDE4D5 and is a multifunctional protein that plays pivotal roles in signal transduction. It functions as an adaptor protein in the c-Raf/MEK/ERK cascade by interacting with c-Raf and ERK ...
Purified C5AR1 CHO-K1 β-Arrestin GPCR Assay Kit from Creative Biomart. C5AR1 CHO-K1 β-Arrestin GPCR Assay Kit can be used for research.
Purified CCR4 CHO-K1 β-Arrestin GPCR Assay Kit from Creative Biomart. CCR4 CHO-K1 β-Arrestin GPCR Assay Kit can be used for research.
GPCRs have important roles in mediating fundamental physiological processes such as vision, olfaction, cardiovascular function, and pain perception. Cellular communication through GPCRs requires the coordination of processes governing receptor activation, desensitization, and resensitization. However, the relative contribution of desensitization mechanisms to the overall homeostatic process still remains largely unexplored in vivo. GPCR kinases (GRKs) act to phosphorylate activated receptors and promote their interaction with β-arrestins. This, in turn, prevents further coupling with G proteins and disrupts normal activation of the second messenger signaling cascade. By this mechanism, GRKs and β-arrestins can act to dampen GPCR signaling, thereby leading to desensitization of the receptor (1). At least six GRKs (GRK1 to GRK6) and four arrestins (visual and cone arrestin, β-arrestins 1 and 2) have been discovered; however, the functional importance of such redundancy is unclear. ...
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Our recent work established the essential role of β-arrestin in the internalization of the M2 mAChR [9]. The present study extends the observations of previous work and demonstrates that the agonist-promoted down-regulation of M1 and M2 mAChRs is β-arrestin dependent, and that the ubiquitination pattern of β-arrestin has a critical role in the differential down-regulation for M1 vs M2 mAChRs.. It has been previously established in a variety of cell lines that a prolonged activation of M1 or M2 mAChRs induces receptor down-regulation. In agreement with these findings, long-term stimulation of M1 or M2 mAChRs induced receptor down-regulation with the M1 mAChR showing significantly more down-regulation than M2 subtype. This observation suggests that the two subtypes are differentially regulated by endogenous β-arrestins. No down-regulation of either mAChR subtype occurred in the absence of β-arrestin and either β-arrestin subtype was able to rescue receptor down-regulation.. The observations ...
Rationale: MicroRNAs (miRs) are small, non-coding RNAs that function to post-transcriptionally regulate gene expression. First transcribed as long primary miR transcripts (pri-miRs), they are enzymatically processed in the nucleus by Drosha into hairpin intermediate miRs (pre-miRs) and further processed in the cytoplasm by Dicer into mature miRs where they regulate cellular processes following activation by a variety of signals such as those stimulated by β-adrenergic receptors (βARs). Initially discovered to desensitize βAR signaling, β-arrestins are now appreciated to transduce multiple effector pathways independent of G protein-mediated second messenger accumulation, a concept known as biased signaling. We previously showed that the β-arrestin-biased βAR agonist carvedilol activates cellular pathways in the heart. Objective: Here, we tested whether carvedilol could activate β-arrestin-mediated miR maturation, thereby providing a novel potential mechanism for its cardioprotective ...
The nuclear translocation of ERKs is normally regulated by the phosphorylation status of MEK1 (Whitmarsh and Davis, 1999). MEK1 binds to ERKs and prevents nuclear translocation of ERKs by its nucleus export signal. Phosphorylation of MEK1 leads to the activation of ERKs and the dissociation of MEK1-ERK complexes, which results in the subsequent nuclear translocation of activated ERKs. In several Gq-coupled GPCR systems, the G protein-dependent pathway activates ERKs through PKC, and the activated ERKs translocate into the nucleus, whereas the β-arrestin functions as a scaffold for both MEK1 and ERKs, thereby preventing the nuclear translocation of β-arrestin-activated ERKs (Tohgo et al., 2002; Shenoy and Lefkowitz, 2005). In addition, the prevention of the nuclear translocation of β-arrestin-activated ERKs is related to the interaction between receptor and β-arrestin. With the reduction in receptor-β-arrestin interaction allowing the recycling of the internalized receptor, a certain amount ...
Cardiac fibroblasts (CF) produce and degrade extracellular matrix and are critical in regulating myocardial remodeling which can lead to heart failure. β-arrestins regulate G protein-coupled receptor (GPCR) function and also mediate GPCR-independent signaling. This study investigates the role of β-arrestin signaling in adult human CF isolated from normal and failing left ventricles. β-arrestin-1 expression is increased 1.5-fold in failing CF relative to normal controls. siRNA-mediated knockdown of β-arrestin 1 or 2 in failing CF decreased the expression of α-smooth muscle actin, suggesting that β-arrestins play an important role in the transformation of CF to activated myofibroblasts in the failing ventricle. This effect was more pronounced by decreasing β-arrestin 1 expression. Knockdown of β-arrestin 1 or 2 in failing CF led to increased β-agonist-stimulated cAMP production and restoration of β-agonist-mediated inhibition of collagen synthesis similar to normal CF. This effect was ...
We have previously shown that fMLP, C3a, and C5a stimulated CCL2 production in a human mast cell line, HMC-1 (8). We suggested that chemoattractant receptor-induced ERK phosphorylation interacts synergistically with Ca2+/calcineurin-dependent activation of NFAT to induce chemokine gene expression (8). Receptor phosphorylation by GRK and subsequent β-arrestin-mediated internalization via clathrin-coated pits is an important mechanism for activation of ERK by a number of G protein-coupled receptors (27, 28). This raises the possibility that chemoattractant receptor-induced chemokine production could involve receptor phosphorylation and β-arrestin-dependent ERK activation. To test this possibility, transient transfectants were generated in RBL-2H3 cells coexpressing C3aR or ΔST-C3aR and βarr2-GFP conjugate. As shown in Fig. 4⇓A, C3a caused a rapid translocation of βarr2-GFP from the cytosol to the membrane in C3aR cells. In contrast, C3a did not induce this response in ΔST-C3aR cells. PTX, ...
We have previously shown that fMLP, C3a, and C5a stimulated CCL2 production in a human mast cell line, HMC-1 (8). We suggested that chemoattractant receptor-induced ERK phosphorylation interacts synergistically with Ca2+/calcineurin-dependent activation of NFAT to induce chemokine gene expression (8). Receptor phosphorylation by GRK and subsequent β-arrestin-mediated internalization via clathrin-coated pits is an important mechanism for activation of ERK by a number of G protein-coupled receptors (27, 28). This raises the possibility that chemoattractant receptor-induced chemokine production could involve receptor phosphorylation and β-arrestin-dependent ERK activation. To test this possibility, transient transfectants were generated in RBL-2H3 cells coexpressing C3aR or ΔST-C3aR and βarr2-GFP conjugate. As shown in Fig. 4⇓A, C3a caused a rapid translocation of βarr2-GFP from the cytosol to the membrane in C3aR cells. In contrast, C3a did not induce this response in ΔST-C3aR cells. PTX, ...
β-Arrestins are ubiquitously expressed and function in the activation of GPCRs, desensitization of most 7-transmembrane receptors, and regulation of other signaling molecules such as protein kinases. For GPCRs, ligand-induced β-arrestin recruitment activates signaling cascades independent of G-protein signaling to provide a non-amplified signal which is ideal for antagonist mode screening, studying ligand pharmacologies, and deorphanizing GPCRs. With decades of experience and hundreds of customer publications, DiscoverX provides a complete set of tools to analyze β-arrestin biology. The PathHunter β-arrestin assays and reagents offer a powerful and universal screening and profiling platform that can be used for virtually any Gi-, Gs-, or Gq-coupled receptor ...
Using Drosophila as a model system, Lee and Montell uncovered a surprising divergence between the pathway leading to light-induced blindness and that underlying retinal degeneration. In many vertebrates, sustained exposure to even low-intensity light leads to blindness, which has long been attributed to the retinal degeneration that takes place under these conditions. Lee and Montell showed that Drosophila exposed to continuous light also displayed a progressive reduction in the visual response (measured with an electroretinogram), as well as retinal degeneration. The photoresponse was substantially reduced after 9 days of exposure to continuous light and drastically reduced--or abolished--after 17 days of exposure. Western analysis of head extracts indicated that the concentration of Rh1, the major rhodopsin, declined in parallel with attenuation of the photoresponse, whereas that of various other signaling proteins did not. Genetic analysis revealed that mutations in arrestin (which encodes a ...
Mdm2 is a ubiquitin-protein ligase known to ubiquitinate p53, promoting its degradation by the ubiquitin-proteasome system. Shenoy and co-workers showed that Mdm2 can act as a key factor in the sequestration of the cell surface β2-adrenergic receptor (β-AR) through interactions with β-arrestin. Strous and Schantl discuss how Mdm2 may be a switch connecting extracellular signals mediated through G protein-coupled receptors (GPCRs) to p53 and its functions in apoptosis and cell cycle progression.. ...
LinkLight™ U2-OS GPR101 / β-arrestin Cell Line is a stable monoclonal cell line in U2-OS cells, targeting Human GPR101 pathway via b-arrestin. The proprietary LinkLight™ technology uses a standard Luciferase Assay as the detection method. Bon Opus Cat. #BC050061
Fingerprint Dive into the research topics of β-Arrestin 2: A receptor-regulated MAPK scaffold for the activation of JNK3. Together they form a unique fingerprint. ...
Pleiotropic G-protein activation 2. Selective G-protein activation 3. Selective G-protein activation 4. Receptor dimerization 5. β-arrestin-Receptor interaction 9. 6. Receptor internalization 7. Receptor/Co-protein interaction 8. 8. β-arrestin-associated signaling 9. 24 Schematic showing some of the properties of seven transmembrane receptors. While many of these behaviors are interdependent upon each other, others are not, and receptors can be made to demonstrate partial panels of these behaviors selectively through binding of different ligands. In fact, new vantage points to view agonist activity can lead to reclassification of ligands. 23 shows a collection of β-blockers reclassified in terms of their activity on β-adrenoceptors as activators of Gproteins and ERK via β-arrestin binding [16,17]. This polyfunctional view of receptors extends beyond cellular signaling, as it is now known that modification of receptor behavior does not require activation of conventional signaling pathways. ...
Starting research in the Caron lab has been an exciting, yet terrifying experience. As the recipient of prestigious awards such as the Lieber Prize for Outstanding Achievement in Schizophrenia Research, Dr. Caron has set the standards high for his lab.. Upon first arriving, I was thrown in at the deep end and expectations were high. I witnessed many procedures and took notes as I watched, hoping that I would be able to replicate the techniques on my own when needed. Such is the case with transfecting and splitting cells, which is how I spent most of my time in lab this past week. While my mentor, Tom Pack, no longer has to overbook the hood for me (though he still does just in case), I find that I still have much to learn in the next 7 weeks.. As the summer progresses, I hope to not only increase my technical proficiency in lab, but also gain a greater understanding of GPCR signaling and the lab equipment that exists for studying it. While my current focus is on arrestin signaling following ...
In cardiac fibroblasts and MEFs, our data indicate that the α1ARs make the primary contribution to ERK activation, supporting the dominant roles of these receptor subtypes in cardiac remodeling.34 Consistent with previous studies,35 stimulation of the α1ARs with Phe induces the classic Gq-dependent activation of PLC and PKC, leading to ERK activation through Raf-MEK1 kinase cascade. Under this signaling cascade, activated ERK translocates to the nucleus.35 Interestingly, this scenario is completely reshaped when β2ARs are coactivated with the α1AR on Epi stimulation. Coactivation of the α1 and β2ARs leads to sequestration of phospho-ERK within the cytosol. Under Epi stimulation, it was possible that two pools of ERK existed; a transient pool activated by the β2AR and a prolonged pool activated by the α1AR. The first pool becomes dominant simply because β2ARs are more prominent in cardiac tissues than α1ARs. This explanation is unlikely for several reasons. First, α1AR antagonist ...
By contrast, specific inhibition of endogenous GRK2 by dominant-negative mutants robustly inhibited OTR phosphorylation and internalization as well as arrestin/OTR interactions ...
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The complete amino acid sequence of bovine S antigen (48-kDa protein) has been determined by cDNA and partial amino acid sequencing. A 1623-base-pair (bp) cDNA contains an open reading frame coding for a protein of 404 amino acids (45,275 Da). Tryptic peptides and cyanogen bromide peptides of native bovine S antigen were purified and partially sequenced. All of these peptides were accounted for in the long open reading frame. Searching of the National Biomedical Research Foundation data bank revealed no extensive sequence homology between S antigen and other proteins. However, there are local regions of sequence similarity with alpha transducin, including the sites subject to ADP-ribosylation by Bordetella pertussis and cholera toxins and the phosphoryl binding-sites. Secondary structure prediction and circular dichroic spectroscopy show that S antigen is composed predominantly of beta-sheet conformation. Acid-catalyzed methanolysis suggests the presence of low levels of carbohydrate in the ...
This study suggests that, unlike the mechanisms of β2 adrenoceptor regulation (Zhang et al., 1997b; Oakley et al., 1999; Gainetdinov et al., 2004), MOR resensitization in LC neurons does not require βarr-2-dependent mechanisms. When MOR endocytosis was presumably impaired by deletion of βarr-2, disruption of GRK2 function, or disruption of dynamin function, MOR resensitization was similarly accelerated rather than inhibited. Furthermore, intracellular application of a phosphatase inhibitor in the absence of βarrestin-dependent receptor trafficking (GRK2 inhibition in βarr-2 k.o.) prevented full recovery of MOR function, suggesting that MOR dephosphorylation is required for MOR resensitization and that this can occur independently of βarr-2-dependent MOR trafficking and endocytosis. The ability of MOR to dephosphorylate and resensitize rapidly when GRK2 and βarr-2 processes are disrupted is consistent with the observation that blocking endocytosis with concanavalin A in cultured LC neurons ...
In the current study, the most important question was whether GRK2 negatively controlled the insulin-induced Akt/eNOS pathway in aortas from diabetic mice with hyperinsulinemia. An important vascular action of insulin is its vasodilator effect, which is associated with increased NO production by endothelial cells (4,5,22,23). The results shown in the present Fig. 1A and B are consistent with our previous report (14). In that previous report, we discussed why GRK2 was increased in the diabetic aorta and how it affected the dysfunction of the endothelium-dependent relaxation to insulin that is mediated via the Akt pathway. We drew the conclusion that PKC activation mediated GRK2 overactivation and that the upregulation of GRK2 led to inhibition of the insulin-induced stimulation of the Akt/eNOS pathway (14). In the current study, we were interested in the pathway downstream of GRK2. From the results, we can propose that GRK2 acts by competing for β-arrestin 2 upon insulin-induced Akt/eNOS ...
• Experimental autoimmune uveitis was observed following the adoptive transfer of T cell lymphocytes (T cells) from Lewis rats previously immunized with a small
Mollusks and human are different species, but because of convergent evolution that led them to have similar genetic expression. There have been studies that proved octopus eyes are similar to humans. In their study, they used a set of 1052 genes of the octopus eye and 13 303 genes of the human eye. For one of the research, they discovered that the protein in the eye were similar. When then compared the genes, they identified that a total of 729 genes were commonly expressed, a total of 69.3%. On other various tests,they found that six3, lhx2, retinal arrestin, retinal dehydrogenase, and human nuclear-transport receptor karyopherin were found to be expressed in the octopus eye ...
The varied behavioral effects of kappa opioid receptors (KOR) are mediated through different signaling cascades. KOR activation of G protein-dependent signaling results in analgesia, whereas the dysphoric effects are mediated by a different pathway involving G protein-coupled receptor kinase (GRK) and arrestin. Therefore, a partial KOR agonist that does not efficiently activate arrestin-dependent signaling may produce analgesia without dysphoria. No selective KOR partial agonists are currently available, and preclinical assessment is complicated by sequence differences between rodent (r) and human (h) KOR. KOR antagonists are also of therapeutic interest for their potential anxiolytic and antidepressant effects, but many KOR antagonists have long durations of action resulting from selective activation of cJun kinase (JNK). In this thesis, I compared the signaling events initiated by agonist stimulation of hKOR and rKOR. Although a partial agonist at both hKOR and rKOR, pentazocine was more ...
Figure 1. Immunolocalization of CNTFRα in the adult mouse retina. A: Negative control. B: Pattern of immunoenzymatic labeling with the anti-chick CNTFRα antibody. C: Pattern of immunoenzymatic labeling with the anti-rat CNTFRα antibody. D: Sequential section (to B) labeled with mouse cone arrestin antibody. E: Immunofluorescence labeling (overlaid images) with the anti-chick CNTFRα antibody (green), DAPI (blue), and peanut agglutinin (red). Intense labeling with the CNTFRα antibodies (B,E) was limited to ganglion cells, nerve fibers, and cells located predominantly at the vitreal and scleral borders of the inner nuclear layer (INL). Less intense labeling was also present at the inner plexiform layer (IPL) and outer plexiform layer (OPL). Nonspecific staining was observed at the photoreceptor layer (A-C) and was distinct from the specific cone inner segment labeling (arrows in D) obtained with the mouse cone arrestin antibody. Fluorescence immunocytochemistry confirmed the absence of ...
Ubiquitously reduced signaling via Methuselah (MTH), a G-protein-coupled receptor (GPCR) required for neurosecretion, has previously been reported to extend life and enhance stress resistance in flies. Whether these effects are due to reduced MTH signalling in specific tissues remains unknown. We determined that reduced expression of mth targeted to the insulin-producing cells (IPCs) of the fly brain was sufficient to extend life and enhance oxidative stress resistance. Paradoxically, we discovered that overexpression of mth targeted to the same cells has similar phenotypic effects to reduced expression due to MTHs interaction with β-arrestin, which uncouples GPCRs from their G-proteins. We confirmed the functional relationship between MTH and β-arrestin by finding that IPC-targeted overexpression of β-arrestin alone mimics the longevity phenotype of reduced MTH signaling. As reduced MTH signaling also inhibits insulin secretion from the IPCs, the most parsimonious mechanistic explanation of ...
Heptahelical G protein-coupled receptors are the most diverse and therapeutically important family of receptors in the human genome. Ligand binding activates heterotrimeric G proteins that transmit intracellular signals by regulating effector enzymes or ion channels. G protein signaling is terminated, in large part, by arrestin binding, which uncouples the receptor and G protein and targets the receptor for internalization. It is clear, however, that heptahelical receptor signaling does not end with desensitization. Arrestins bind a host of catalytically active proteins and serve as ligand-regulated scaffolds that recruit protein and lipid kinase, phosphatase, phosphodiesterase, and ubiquitin ligase activity into the receptor-arrestin complex. Although many of these arrestin-bound effectors serve to modulate G protein signaling, degrading second messengers and regulating endocytosis and trafficking, other signals seem to extend beyond the receptor-arrestin complex to regulate such processes as ...
Figure 12. GPCR and heterotrimeric G-protein signalling.. The ligand bound to the GPCR is shown in red. Binding allows the exchange of GDP for GTP by the associated G protein, and dissociation of the protein into Gα and Gβγ subunits. These then have downstream effects on a range of proteins, thereby propagating the signal from the bound ligand. Yellow arrows indicate either activation (up arrow) or inhibition (down arrow) of the targets. Regulators of G-protein signalling (RGS) proteins aid the GTPase activity of the G protein to turn off the signal. Arrestin can bind the receptor following GPCR phosphorylation by G-protein receptor kinase (GRK), desensitizing the receptor to further signalling. Reproduced from Berridge, M.J. (2012) Cell Signalling Biology; doi:10.1042/csb0001002, with permission. ...
The Genetics Society of America (GSA), founded in 1931, is the professional membership organization for scientific researchers and educators in the field of genetics. Our members work to advance knowledge in the basic mechanisms of inheritance, from the molecular to the population level.. Online ISSN: 1943-2631. ...
In this study, we have adopted a proteomic approach to characterize new ligands of the TCR‐signaling ITAM motifs. In this way, we identified the GPCR‐interacting protein β‐Arr1 as a novel direct ligand of the TCR that is recruited to unphosphorylated ITAMs in a manner dependent on TCR triggering. While β‐Arr1 was previously described as a cytoplasmic effector of both GPCRs and RTKs (Hupfeld & Olefsky, 2007), this is the first demonstration of β‐Arr1 binding to the TCR, a multi‐subunit receptor without intrinsic enzymatic activity. We found that β‐Arr1 recruitment to the TCR was induced by TCR triggering. However, in contrast to the recruitment of other TCR signaling effectors, such as the tyrosine kinase ZAP‐70 or the adaptor protein Nck (Gil et al, 2002), that is mediated by changes in the TCR itself, recruitment of β‐Arr1 to the TCR was mediated by modifying β‐Arr1. The mechanism by which TCR triggering induces the recruitment of β‐Arr1 to non‐triggered TCRs ...
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InterPro provides functional analysis of proteins by classifying them into families and predicting domains and important sites. We combine protein signatures from a number of member databases into a single searchable resource, capitalising on their individual strengths to produce a powerful integrated database and diagnostic tool.
p>The checksum is a form of redundancy check that is calculated from the sequence. It is useful for tracking sequence updates.,/p> ,p>It should be noted that while, in theory, two different sequences could have the same checksum value, the likelihood that this would happen is extremely low.,/p> ,p>However UniProtKB may contain entries with identical sequences in case of multiple genes (paralogs).,/p> ,p>The checksum is computed as the sequence 64-bit Cyclic Redundancy Check value (CRC64) using the generator polynomial: x,sup>64,/sup> + x,sup>4,/sup> + x,sup>3,/sup> + x + 1. The algorithm is described in the ISO 3309 standard. ,/p> ,p class=publication>Press W.H., Flannery B.P., Teukolsky S.A. and Vetterling W.T.,br /> ,strong>Cyclic redundancy and other checksums,/strong>,br /> ,a href=http://www.nrbook.com/b/bookcpdf.php>Numerical recipes in C 2nd ed., pp896-902, Cambridge University Press (1993),/a>),/p> Checksum:i ...
This gene encodes a thioredoxin-binding protein that is a member of the alpha arrestin protein family. Thioredoxin is a thiol-oxidoreductase that is a major regulator of cellular redox signaling which protects cells from oxidative stress. This protein inhibits the antioxidative function of thioredoxin resulting in the accumulation of reactive oxygen species and cellular stress. This protein also functions as a regulator of cellular metabolism and of endoplasmic reticulum (ER) stress. This protein may also function as a tumor suppressor. Alternate splicing results in multiple transcript variants. [provided by RefSeq, Sep 2015 ...
Plays a critical role in eye formation by regulating the initial specification of retinal cells and/or their subsequent proliferation. Binds to the photoreceptor conserved element-I (PCE-1/Ret 1) in the photoreceptor cell-specific arrestin promoter.
TY - JOUR. T1 - Differential expression of alternative splice variants of β-arrestin-1 and -2 in rat central nervous system and peripheral tissues. AU - Komori, Naoka. AU - Cain, Sandra D.. AU - Roch, Jean Marc. AU - Miller, Kenneth E.. AU - Matsumoto, Hiroyuki. N1 - Copyright: Copyright 2007 Elsevier B.V., All rights reserved.. PY - 1998. Y1 - 1998. N2 - Members of arrestin/β-arrestin protein family are thought to participate in agonist-mediated desensitization of G-protein-coupled receptors, including rhodopsin and β2-adrenergic receptor. Unlike in human and cow, splice variants of this protein family in rat have not been studied extensively, and there has been no report on their existence at protein level. Hence, a previous report by others on the localization of both β-arrestin-1 and -2 in a wide range of innervated rat tissues could imply their broad receptor specificity. In this report we show the presence of two alternatively spliced forms of β-arrestin-1 in several rat tissues using ...
TXNIP is a member of the α-arrestin family that functions as an intracellular scaffold, which participates in cellular signaling by formation of signaling complexes and localization of signaling components in the cell.11,12 VEGF-VEGFR2 signaling in EC seems to be dependent on TXNIP as shown in the present study. We showed previously that TXNIP was required for VEGFR2 activation and EC survival in response to low concentrations of H2O2 and tumor necrosis factor-α.15 These data support our concept that TXNIP plays a critical role in regulating VEGFR2 signaling and angiogenesis in EC.. A novel finding of the present study is that TXNIP seems to be required for the earliest stage of VEGFR2 internalization. Receptor tyrosine kinases are regulated by endocytosis through the internalization of plasma membrane receptors.25-27 For example, the internalization of epidermal growth factor receptor is mediated by clathrin-mediated endocytosis and is essential for sustained epidermal growth factor receptor ...
Although many different mutations in humans and Drosophila cause retinal degeneration, in most cases, a molecular mechanism for the degeneration has not been found. We now demonstrate the existence of stable, persistent complexes between rhodopsin and its regulatory protein arrestin in several diffe …
TY - JOUR. T1 - Distinct CCK-2 Receptor Conformations Associated with β-Arrestin-2 Recruitment or Phospholipase-C Activation Revealed by a Biased Antagonist. AU - Magnan, Rémi. AU - Escrieut, Chantal. AU - Gigoux, Véronique. AU - De, Kavita. AU - Clerc, Pascal. AU - Niu, Fan. AU - Azema, Joelle. AU - Masri, Bernard. AU - Cordomi, Arnau. AU - Baltas, Michel. AU - Tikhonova, Irina G. AU - Fourmy, Daniel. PY - 2013/2/20. Y1 - 2013/2/20. N2 - Seven-transmembrane receptors (7TMRs), also termed G protein-coupled receptors (GPCRs), form the largest class of cell surface membrane receptors, involving several hundred members in the human genome. Near 30% of marketed pharmacological agents target 7TMRs. 7TMRs adopt multiple conformations upon agonist binding. Biased agonists, in contrast to non-biased agonists, are believed to stabilize conformations preferentially activating either G-protein- or ß-arrestin-dependent signalling pathways. However, proof that cognate conformations of receptors display ...
TY - JOUR. T1 - β-arrestin-biased agonism of β-adrenergic receptor regulates Dicer-mediated microRNA maturation to promote cardioprotective signaling. AU - Teoh, Jian Peng. AU - Bayoumi, Ahmed S.. AU - Aonuma, Tatsuya. AU - Xu, Yanyan. AU - Johnson, John A.. AU - Su, Huabo. AU - Weintraub, Neal L.. AU - Tang, Yaoliang. AU - Kim, Il Man. PY - 2018/5. Y1 - 2018/5. N2 - Rationale: MicroRNAs (miRs) are small, non-coding RNAs that function to post-transcriptionally regulate target genes. First transcribed as primary miR transcripts (pri-miRs), they are enzymatically processed by Drosha into premature miRs (pre-miRs) and further cleaved by Dicer into mature miRs. Initially discovered to desensitize β-adrenergic receptor (βAR) signaling, β-arrestins are now well-appreciated to modulate multiple pathways independent of G protein signaling, a concept known as biased signaling. Using the β-arrestin-biased βAR ligand carvedilol, we previously showed that β-arrestin1 (not β-arrestin2)-biased β1AR ...
3. Berchiche Y.A., Gravel S., Pelletier M-E.,Ste-Onge G., Heveker N. Different effects of the different natural CCR2 ligands on β-arrestin recruitment, Gαi signalling and receptor internalization.(2011) Molecular Pharmacology 79(3):488-98. http://www.ncbi.nlm.nih.gov/pubmed/21088225. 4. Gravel S. Malouf C., Boulais P., Berchiche Y.A., Oishi S., Fujii N., Leduc R., Sinnett D., Heveker N. The Peptidomimetic CXCR4 antagonist TC14012 Recruits Beta-Arrestin to CXCR7-Roles of Receptor Domains.(2010) Journal of Biological Chemistry 285(49):37939-43. http://www.ncbi.nlm.nih.gov/pubmed/20956518. 5. Kalatskaya I*, Berchiche Y.A.*, Gravel S, Limberg B. J., Rosenbaum J.S, Heveker N. AMD3100 is a CXCR7 Ligand with Allosteric Agonist Properties. (2009) Molecular Pharmacology 75:1-8. * Contributed equally to this work. http://www.ncbi.nlm.nih.gov/pubmed/19255243. 6. Rafei M., Berchiche Y.A., Birman E., Boivin MN., Young Y.K., Wu J. H., Heveker N., Galipeau J. An Engineered GMCSF-CCL2 Fusokine is a Potent ...
The mechanism of PAR1 activation is strikingly irreversible. Cleavage of PAR1 by thrombin is irrevocable, and the tethered ligand generated cannot diffuse away from the receptor. In the absence of the reversible ligation that characterizes most receptor systems, how is PAR1 shut off? The β2-adrenergic receptor has served as a prototype for dissecting the molecular events responsible for G protein-coupled receptor desensitization and resensitization (10-13). Upon activation, β2-adrenergic receptor is rapidly phosphorylated. It then binds arrestin, preventing further interaction with G proteins. Arrestin also mediates internalization of β2-adrenergic receptors via clathrin-coated pits (14, 15). Within an endosomal compartment, receptors dissociate from ligand, are dephosphorylated, and recycle back to the cell surface competent to signal again. Thus trafficking serves to remove activated β2-adrenergic receptors from the cell surface and to return the receptors to the surface in an off state, ...
Zhu X, Brown B, Li A et al. (2003). GRK1-dependent phosphorylation of S and M opsins and their binding to cone arrestin during cone phototransduction in the mouse retina.. J. Neurosci. 23 (14): 6152-60. PMID 12853434. CS1 održavanje: Eksplicitna upotreba et al. (link) ...
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