The Experts below are selected from a list of 4299 Experts worldwide ranked by ideXlab platform
Robert J Lefkowitz - One of the best experts on this subject based on the ideXlab platform.
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β-Arrestin-dependent signaling and trafficking of 7-transmembrane receptors is reciprocally regulated by the deubiquitinase USP33 and the E3 ligase Mdm2
Proceedings of the National Academy of Sciences of the United States of America, 2009Co-Authors: Sudha K Shenoy, William E Miller, Arun K Shukla, Seungkirl Ahn, Aalok S. Modi, Kunhong Xiao, Magali Berthouze, Keith D. Wilkinson, Robert J LefkowitzAbstract:Beta-Arrestins are multifunctional adaptors that mediate the desensitization, internalization, and some signaling functions of seven-transmembrane receptors (7TMRs). Agonist-stimulated ubiquitination of Beta-Arrestin2 mediated by the E3 ubiquitin ligase Mdm2 is critical for rapid Beta(2)-adrenergic receptor (Beta(2)AR) internalization. We now report the discovery that the deubiquitinating enzyme ubiquitin-specific protease 33 (USP33) binds Beta-Arrestin2 and leads to the deubiquitination of Beta-Arrestins. USP33 and Mdm2 function reciprocally and favor respectively the stability or lability of the receptor Beta-Arrestin complex, thus regulating the longevity and subcellular localization of receptor signalosomes. Receptors such as the Beta(2)AR, previously shown to form loose complexes with Beta-Arrestin ("class A") promote a Beta-Arrestin conformation conducive for binding to the deubiquitinase, whereas the vasopressin V2R, which forms tight Beta-Arrestin complexes ("class B"), promotes a distinct Beta-Arrestin conformation that favors dissociation of the enzyme. Thus, USP33-Beta-Arrestin interaction is a key regulatory step in 7TMR trafficking and signal transmission from the activated receptors to downstream effectors.
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The sustainability of interactions between the orexin-1 receptor and Beta-Arrestin-2 is defined by a single C-terminal cluster of hydroxy amino acids and modulates the kinetics of ERK MAPK regulation.
The Biochemical journal, 2005Co-Authors: Sandra Milasta, Robert J Lefkowitz, Nicholas A. Evans, Shelagh Wilson, Laura Ormiston, Graeme MilliganAbstract:The orexin-1 receptor interacts with Beta-Arrestin-2 in an agonist-dependent manner. In HEK-293T cells, these two proteins became co-internalized into acidic endosomes. Truncations from the C-terminal tail did not prevent agonist-induced internalization of the orexin-1 receptor or alter the pathway of internalization, although such mutants failed to interact with Beta-Arrestin-2 in a sustained manner or produce its co-internalization. Mutation of a cluster of three threonine and one serine residue at the extreme C-terminus of the receptor greatly reduced interaction and abolished co-internalization of Beta-Arrestin-2-GFP (green fluorescent protein). Despite the weak interactions of this C-terminally mutated form of the receptor with Beta-Arrestin-2, studies in wild-type and Beta-Arrestin-deficient mouse embryo fibroblasts confirmed that agonist-induced internalization of this mutant required expression of a Beta-Arrestin. Although without effect on agonist-mediated elevation of intracellular Ca2+ levels, the C-terminally mutated form of the orexin-1 receptor was unable to sustain phosphorylation of the MAPKs (mitogen-activated protein kinases) ERK1 and ERK2 (extracellular-signal-regulated kinases 1 and 2) to the same extent as the wild-type receptor. These studies indicate that a single cluster of hydroxy amino acids within the C-terminal seven amino acids of the orexin-1 receptor determine the sustainability of interaction with Beta-Arrestin-2, and indicate an important role of Beta-Arrestin scaffolding in defining the kinetics of orexin-1 receptor-mediated ERK MAPK activation.
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Beta Arrestin 1 and galphaq 11 coordinately activate rhoa and stress fiber formation following receptor stimulation
Journal of Biological Chemistry, 2005Co-Authors: William G Barnes, Graeme Milligan, Eric Reiter, Jonathan D Violin, Xiurong Ren, Robert J LefkowitzAbstract:Beta-Arrestins were initially shown, in conjunction with G protein-coupled receptor kinases, to be involved in the desensitization and internalization of activated seven-transmembrane receptors. Recently, Beta-Arrestin 2 has been shown to act as a signal mediator in mitogen-activated protein kinase cascades and to play a positive regulatory role in chemotaxis. We now show that Beta-Arrestin 1 is required to activate the small GTPase RhoA leading to the re-organization of stress fibers following the activation of the angiotensin II type 1A receptor. This angiotensin II type 1A receptor-directed RhoA activation and stress fiber formation also require the activation of the heterotrimeric G protein G(alphaq/11). Whereas neither Beta-Arrestin 1 nor G(alphaq/11) activation alone is sufficient to robustly activate RhoA, the concurrent recruitment of Beta-Arrestin 1 and activation of G(alphaq/11) leads to full activation of RhoA and to the subsequent formation of stress fibers.
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Beta-Arrestin 1 and Galphaq/11 coordinately activate RhoA and stress fiber formation following receptor stimulation.
The Journal of biological chemistry, 2004Co-Authors: William G Barnes, Graeme Milligan, Eric Reiter, Jonathan D Violin, Xiurong Ren, Robert J LefkowitzAbstract:Beta-Arrestins were initially shown, in conjunction with G protein-coupled receptor kinases, to be involved in the desensitization and internalization of activated seven-transmembrane receptors. Recently, Beta-Arrestin 2 has been shown to act as a signal mediator in mitogen-activated protein kinase cascades and to play a positive regulatory role in chemotaxis. We now show that Beta-Arrestin 1 is required to activate the small GTPase RhoA leading to the re-organization of stress fibers following the activation of the angiotensin II type 1A receptor. This angiotensin II type 1A receptor-directed RhoA activation and stress fiber formation also require the activation of the heterotrimeric G protein G(alphaq/11). Whereas neither Beta-Arrestin 1 nor G(alphaq/11) activation alone is sufficient to robustly activate RhoA, the concurrent recruitment of Beta-Arrestin 1 and activation of G(alphaq/11) leads to full activation of RhoA and to the subsequent formation of stress fibers.
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dishevelled 2 recruits Beta Arrestin 2 to mediate wnt5a stimulated endocytosis of frizzled 4
Science, 2003Co-Authors: Wei Chen, Roel Nusse, Marc G Caron, Derk Ten Berge, J M Brown, Liaoyuan A Hu, William E Miller, Larry S Barak, Robert J LefkowitzAbstract:Wnt proteins, regulators of development in many organisms, bind to seven transmembrane-spanning (7TMS) receptors called frizzleds, thereby recruiting the cytoplasmic molecule dishevelled (Dvl) to the plasma membrane.Frizzled-mediated endocytosis of Wg (a Drosophila Wnt protein) and lysosomal degradation may regulate the formation of morphogen gradients. Endocytosis of Frizzled 4 (Fz4) in human embryonic kidney 293 cells was dependent on added Wnt5A protein and was accomplished by the multifunctional adaptor protein Beta-Arrestin 2 (Betaarr2), which was recruited to Fz4 by binding to phosphorylated Dvl2. These findings provide a previously unrecognized mechanism for receptor recruitment of Beta-Arrestin and demonstrate that Dvl plays an important role in the endocytosis of frizzled, as well as in promoting signaling.
Marc G Caron - One of the best experts on this subject based on the ideXlab platform.
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Biased agonists of the chemokine receptor CXCR3 differentially drive formation of Gαi:β-Arrestin complexes
2020Co-Authors: Kevin Zheng, Marc G Caron, Jeffrey S. Smith, Anmol Warman, Issac Choi, Jaimee N. Gundry, Thomas F. Pack, Asuka Inoue, Sudarshan RajagopalAbstract:G-protein-coupled receptors (GPCRs), the largest family of cell surface receptors, signal through the proximal effectors G proteins and {Beta}-Arrestins to influence nearly every biological process. Classically, the G protein and {Beta}-Arrestin signaling pathways have largely been considered separable. Recently, direct interactions between G protein and {Beta}-Arrestin have been described and suggest a distinct GPCR signaling pathway. Within these newly described G:{Beta}-Arrestin complexes, Gi/o, but not other G protein subtypes, have been appreciated to directly interact with {Beta}-Arrestin, regardless of canonical GPCR G protein subtype coupling. However it is unclear how biased agonists differentially regulate this newly described Gi:{Beta}-Arrestin interaction, if at all. Here we report that endogenous ligands (chemokines) of the GPCR CXCR3, CXCL9, CXCL10, and CXCL11, along with two small molecule biased CXCR3 agonists, differentially promote the formation of Gi:{Beta}-Arrestin complexes. The ability of CXCR3 agonists to form Gi:{Beta}-Arrestin complexes does not correlate well with either G protein signaling or {Beta}-Arrestin recruitment. Conformational biosensors demonstrate that ligands that promoted Gi:{Beta}-Arrestin complex formation generated similar {Beta}-Arrestin conformations. We find these Gi:{Beta}-Arrestin complexes can associate with CXCR3, but not with ERK. These findings further support that Gi:{Beta}-Arrestin complex formation is a distinct GPCR signaling pathway and enhance our understanding of biased agonism.
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dishevelled 2 recruits Beta Arrestin 2 to mediate wnt5a stimulated endocytosis of frizzled 4
Science, 2003Co-Authors: Wei Chen, Roel Nusse, Marc G Caron, Derk Ten Berge, J M Brown, Liaoyuan A Hu, William E Miller, Larry S Barak, Robert J LefkowitzAbstract:Wnt proteins, regulators of development in many organisms, bind to seven transmembrane-spanning (7TMS) receptors called frizzleds, thereby recruiting the cytoplasmic molecule dishevelled (Dvl) to the plasma membrane.Frizzled-mediated endocytosis of Wg (a Drosophila Wnt protein) and lysosomal degradation may regulate the formation of morphogen gradients. Endocytosis of Frizzled 4 (Fz4) in human embryonic kidney 293 cells was dependent on added Wnt5A protein and was accomplished by the multifunctional adaptor protein Beta-Arrestin 2 (Betaarr2), which was recruited to Fz4 by binding to phosphorylated Dvl2. These findings provide a previously unrecognized mechanism for receptor recruitment of Beta-Arrestin and demonstrate that Dvl plays an important role in the endocytosis of frizzled, as well as in promoting signaling.
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the stability of the g protein coupled receptor β Arrestin interaction determines the mechanism and functional consequence of erk activation
Journal of Biological Chemistry, 2003Co-Authors: Akira Tohgo, Robert J Lefkowitz, Marc G Caron, Robert H Oakley, Stephane A Laporte, Diane Gestypalmer, Eric W Choy, Kristen L Pierce, Louis M LuttrellAbstract:By binding to agonist-activated G protein-coupled receptors (GPCRs), Beta-Arrestins mediate homologous receptor desensitization and endocytosis via clathrin-coated pits. Recent data suggest that Beta-Arrestins also contribute to GPCR signaling by acting as scaffolds for components of the ERK mitogen-activated protein kinase cascade. Because of these dual functions, we hypothesized that the stability of the receptor-Beta-Arrestin interaction might affect the mechanism and functional consequences of GPCR-stimulated ERK activation. In transfected COS-7 cells, we found that angiotensin AT1a and vasopressin V2 receptors, which form stable receptor-Beta-Arrestin complexes, activated a Beta-Arrestin-bound pool of ERK2 more efficiently than alpha 1b and Beta2 adrenergic receptors, which form transient receptor-Beta-Arrestin complexes. We next studied chimeric receptors in which the pattern of Beta-Arrestin binding was reversed by exchanging the C-terminal tails of the Beta2 and V2 receptors. The ability of the V2 Beta 2 and Beta 2V2 chimeras to activate Beta-Arrestin-bound ERK2 corresponded to the pattern of Beta-Arrestin binding, suggesting that the stability of the receptor-Beta-Arrestin complex determined the mechanism of ERK2 activation. Analysis of covalently cross-linked detergent lysates and cellular fractionation revealed that wild type V2 receptors generated a larger pool of cytosolic phospho-ERK1/2 and less nuclear phospho-ERK1/2 than the chimeric V2 Beta 2 receptor, consistent with the cytosolic retention of Beta-Arrestin-bound ERK. In stably transfected HEK-293 cells, the V2 Beta 2 receptor increased ERK1/2-mediated, Elk-1-driven transcription of a luciferase reporter to a greater extent than the wild type V2 receptor. Furthermore, the V2 Beta 2, but not the V2 receptor, was capable of eliciting a mitogenic response. These data suggest that the C-terminal tail of a GPCR, by determining the stability of the receptor-Beta-Arrestin complex, controls the extent of Beta-Arrestin-bound ERK activation, and influences both the subcellular localization of activated ERK and the physiologic consequences of ERK activation.
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Enhanced morphine analgesia in mice lacking Beta-Arrestin 2.
Science (New York N.Y.), 1999Co-Authors: Laura M. Bohn, Robert J Lefkowitz, Marc G Caron, Raul R. Gainetdinov, Karsten Peppel, Fang-tsyr LinAbstract:The ability of morphine to alleviate pain is mediated through a heterotrimeric guanine nucleotide binding protein (G protein)-coupled heptahelical receptor (GPCR), the mu opioid receptor (muOR). The efficiency of GPCR signaling is tightly regulated and ultimately limited by the coordinated phosphorylation of the receptors by specific GPCR kinases and the subsequent interaction of the phosphorylated receptors with Beta-Arrestin 1 and Beta-Arrestin 2. Functional deletion of the Beta-Arrestin 2 gene in mice resulted in remarkable potentiation and prolongation of the analgesic effect of morphine, suggesting that muOR desensitization was impaired. These results provide evidence in vivo for the physiological importance of Beta-Arrestin 2 in regulating the function of a specific GPCR, the muOR. Moreover, they suggest that inhibition of Beta-Arrestin 2 function might lead to enhanced analgesic effectiveness of morphine and provide potential new avenues for the study and treatment of pain, narcotic tolerance, and dependence.
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association of Beta Arrestin with g protein coupled receptors during clathrin mediated endocytosis dictates the profile of receptor resensitization
Journal of Biological Chemistry, 1999Co-Authors: Robert H Oakley, Larry S Barak, Stephane A Laporte, Jason A Holt, Marc G CaronAbstract:Resensitization of G protein-coupled receptors (GPCRs) following agonist-mediated desensitization is a necessary step for maintaining physiological responsiveness. However, the molecular mechanisms governing the nature of GPCR resensitization are poorly understood. Here, we examine the role of Beta-Arrestin in the resensitization of the Beta(2) adrenergic receptor (Beta(2)AR), known to recycle and resensitize rapidly, and the vasopressin V2 receptor (V2R), known to recycle and resensitize slowly. Upon agonist activation, both receptors recruit Beta-Arrestin to the plasma membrane and internalize in a Beta-Arrestin- and clathrin-dependent manner. However, whereas Beta-Arrestin dissociates from the Beta(2)AR at the plasma membrane, it internalizes with the V2R into endosomes. The differential trafficking of Beta-Arrestin and the ability of these two receptors to dephosphorylate, recycle, and resensitize is completely reversed when the carboxyl-terminal tails of these two receptors are switched. Moreover, the ability of Beta-Arrestin to remain associated with desensitized GPCRs during clathrin-mediated endocytosis is mediated by a specific cluster of phosphorylated serine residues in the receptor carboxyl-terminal tail. These results demonstrate that the interaction of Beta-Arrestin with a specific motif in the GPCR carboxyl-terminal tail dictates the rate of receptor dephosphorylation, recycling, and resensitization, and thus provide direct evidence for a novel mechanism by which Beta-Arrestins regulate the reestablishment of GPCR responsiveness.
Graeme Milligan - One of the best experts on this subject based on the ideXlab platform.
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mutations of Beta Arrestin 2 that limit self association also interfere with interactions with the Beta2 adrenoceptor and the erk1 2 mapks implications for Beta2 adrenoceptor signalling via the erk1 2 mapks
Biochemical Journal, 2008Co-Authors: Tianrui Xu, George S Baillie, David R Adams, Narinder Bhari, Thomas M Houslay, Andrew M Pitt, Walter Kolch, Miles D Houslay, Graeme MilliganAbstract:FRET (fluorescence resonance energy transfer) and co-immunoprecipitation studies confirmed the capacity of Beta-Arrestin 2 to self-associate. Amino acids potentially involved in direct protein-protein interaction were identified via combinations of spot-immobilized peptide arrays and mapping of surface exposure. Among potential key amino acids, Lys(285), Arg(286) and Lys(295) are part of a continuous surface epitope located in the polar core between the N- and C-terminal domains. Introduction of K285A/R286A mutations into Beta-Arrestin 2-eCFP (where eCFP is enhanced cyan fluorescent protein) and Beta-Arrestin 2-eYFP (where eYFP is enhanced yellow fluorescent protein) constructs substantially reduced FRET, whereas introduction of a K295A mutation had a more limited effect. Neither of these mutants was able to promote Beta2-adrenoceptor-mediated phosphorylation of the ERK1/2 (extracellular-signal-regulated kinase 1/2) MAPKs (mitogen-activated protein kinases). Both Beta-Arrestin 2 mutants displayed limited capacity to co-immunoprecipitate ERK1/2 and further spot-immobilized peptide arrays indicated each of Lys(285), Arg(286) and particularly Lys(295) to be important for this interaction. Direct interactions between Beta-Arrestin 2 and the Beta2-adrenoceptor were also compromised by both K285A/R286A and K295A mutations of Beta-Arrestin 2. These were not non-specific effects linked to improper folding of Beta-Arrestin 2 as limited proteolysis was unable to distinguish the K285A/R286A or K295A mutants from wild-type Beta-Arrestin 2, and the interaction of Beta-Arrestin 2 with JNK3 (c-Jun N-terminal kinase 3) was unaffected by the K285A/R286A or L295A mutations. These results suggest that amino acids important for self-association of Beta-Arrestin 2 also play an important role in the interaction with both the Beta2-adrenoceptor and the ERK1/2 MAPKs. Regulation of Beta-Arrestin 2 self-association may therefore control Beta-Arrestin 2-mediated Beta2-adrenoceptor-ERK1/2 MAPK signalling.
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Mutations of β-Arrestin 2 that limit self-association also interfere with interactions with the β2-adrenoceptor and the ERK1/2 MAPKs: implications for β2-adrenoceptor signalling via the ERK1/2 MAPKs
The Biochemical journal, 2008Co-Authors: George S Baillie, David R Adams, Narinder Bhari, Thomas M Houslay, Andrew M Pitt, Walter Kolch, Miles D Houslay, Graeme MilliganAbstract:FRET (fluorescence resonance energy transfer) and co-immunoprecipitation studies confirmed the capacity of Beta-Arrestin 2 to self-associate. Amino acids potentially involved in direct protein-protein interaction were identified via combinations of spot-immobilized peptide arrays and mapping of surface exposure. Among potential key amino acids, Lys(285), Arg(286) and Lys(295) are part of a continuous surface epitope located in the polar core between the N- and C-terminal domains. Introduction of K285A/R286A mutations into Beta-Arrestin 2-eCFP (where eCFP is enhanced cyan fluorescent protein) and Beta-Arrestin 2-eYFP (where eYFP is enhanced yellow fluorescent protein) constructs substantially reduced FRET, whereas introduction of a K295A mutation had a more limited effect. Neither of these mutants was able to promote Beta2-adrenoceptor-mediated phosphorylation of the ERK1/2 (extracellular-signal-regulated kinase 1/2) MAPKs (mitogen-activated protein kinases). Both Beta-Arrestin 2 mutants displayed limited capacity to co-immunoprecipitate ERK1/2 and further spot-immobilized peptide arrays indicated each of Lys(285), Arg(286) and particularly Lys(295) to be important for this interaction. Direct interactions between Beta-Arrestin 2 and the Beta2-adrenoceptor were also compromised by both K285A/R286A and K295A mutations of Beta-Arrestin 2. These were not non-specific effects linked to improper folding of Beta-Arrestin 2 as limited proteolysis was unable to distinguish the K285A/R286A or K295A mutants from wild-type Beta-Arrestin 2, and the interaction of Beta-Arrestin 2 with JNK3 (c-Jun N-terminal kinase 3) was unaffected by the K285A/R286A or L295A mutations. These results suggest that amino acids important for self-association of Beta-Arrestin 2 also play an important role in the interaction with both the Beta2-adrenoceptor and the ERK1/2 MAPKs. Regulation of Beta-Arrestin 2 self-association may therefore control Beta-Arrestin 2-mediated Beta2-adrenoceptor-ERK1/2 MAPK signalling.
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Mapping binding sites for the PDE4D5 cAMP-specific phosphodiesterase to the N- and C-domains of β-Arrestin using spot-immobilized peptide arrays
The Biochemical journal, 2007Co-Authors: George S Baillie, Graeme Milligan, David R Adams, Narinder Bhari, Thomas M Houslay, Allan J. Dunlop, Suryakiran Vadrevu, Dong Meng, Graeme B BolgerAbstract:Beta2-ARs (Beta2-adrenoceptors) become desensitized rapidly upon recruitment of cytosolic Beta-Arrestin. PDE4D5 (family 4 cAMP-specific phosphodiesterase, subfamily D, isoform 5) can be recruited in complex with Beta-Arrestin, whereupon it regulates PKA (cAMP-dependent protein kinase) phosphorylation of the Beta2-AR. In the present study, we have used novel technology, employing a library of overlapping peptides (25-mers) immobilized on cellulose membranes that scan the entire sequence of Beta-Arrestin 2, to define the interaction sites on Beta-Arrestin 2 for binding of PDE4D5 and the cognate long isoform, PDE4D3. We have identified a binding site in the Beta-Arrestin 2 N-domain for the common PDE4D catalytic unit and two regions in the Beta-Arrestin 2 C-domain that confer specificity for PDE4D5 binding. Alanine-scanning peptide array analysis of the N-domain binding region identified severely reduced interaction with PDE4D5 upon R26A substitution, and reduced interaction upon either K18A or T20A substitution. Similar analysis of the Beta-Arrestin 2 C-domain identified Arg286 and Asp291, together with the Leu215-His220 region, as being important for binding PDE4D5, but not PDE4D3. Transfection with wild-type Beta-Arrestin 2 profoundly decreased isoprenaline-stimulated PKA phosphorylation of the Beta2-AR in MEFs (mouse embryo fibroblasts) lacking both Beta-Arrestin 1 and Beta-Arrestin 2. This effect was negated using either the R26A or the R286A mutant form of Beta-Arrestin 2 or a mutant with substitution of an alanine cassette for Leu215-His220, which showed little or no PDE4D5 binding, but was still recruited to the Beta2-AR upon isoprenaline challenge. These data show that the interaction of PDE4D5 with both the N- and C-domains of Beta-Arrestin 2 are essential for Beta2-AR regulation.
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The sustainability of interactions between the orexin-1 receptor and Beta-Arrestin-2 is defined by a single C-terminal cluster of hydroxy amino acids and modulates the kinetics of ERK MAPK regulation.
The Biochemical journal, 2005Co-Authors: Sandra Milasta, Robert J Lefkowitz, Nicholas A. Evans, Shelagh Wilson, Laura Ormiston, Graeme MilliganAbstract:The orexin-1 receptor interacts with Beta-Arrestin-2 in an agonist-dependent manner. In HEK-293T cells, these two proteins became co-internalized into acidic endosomes. Truncations from the C-terminal tail did not prevent agonist-induced internalization of the orexin-1 receptor or alter the pathway of internalization, although such mutants failed to interact with Beta-Arrestin-2 in a sustained manner or produce its co-internalization. Mutation of a cluster of three threonine and one serine residue at the extreme C-terminus of the receptor greatly reduced interaction and abolished co-internalization of Beta-Arrestin-2-GFP (green fluorescent protein). Despite the weak interactions of this C-terminally mutated form of the receptor with Beta-Arrestin-2, studies in wild-type and Beta-Arrestin-deficient mouse embryo fibroblasts confirmed that agonist-induced internalization of this mutant required expression of a Beta-Arrestin. Although without effect on agonist-mediated elevation of intracellular Ca2+ levels, the C-terminally mutated form of the orexin-1 receptor was unable to sustain phosphorylation of the MAPKs (mitogen-activated protein kinases) ERK1 and ERK2 (extracellular-signal-regulated kinases 1 and 2) to the same extent as the wild-type receptor. These studies indicate that a single cluster of hydroxy amino acids within the C-terminal seven amino acids of the orexin-1 receptor determine the sustainability of interaction with Beta-Arrestin-2, and indicate an important role of Beta-Arrestin scaffolding in defining the kinetics of orexin-1 receptor-mediated ERK MAPK activation.
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Beta Arrestin 1 and galphaq 11 coordinately activate rhoa and stress fiber formation following receptor stimulation
Journal of Biological Chemistry, 2005Co-Authors: William G Barnes, Graeme Milligan, Eric Reiter, Jonathan D Violin, Xiurong Ren, Robert J LefkowitzAbstract:Beta-Arrestins were initially shown, in conjunction with G protein-coupled receptor kinases, to be involved in the desensitization and internalization of activated seven-transmembrane receptors. Recently, Beta-Arrestin 2 has been shown to act as a signal mediator in mitogen-activated protein kinase cascades and to play a positive regulatory role in chemotaxis. We now show that Beta-Arrestin 1 is required to activate the small GTPase RhoA leading to the re-organization of stress fibers following the activation of the angiotensin II type 1A receptor. This angiotensin II type 1A receptor-directed RhoA activation and stress fiber formation also require the activation of the heterotrimeric G protein G(alphaq/11). Whereas neither Beta-Arrestin 1 nor G(alphaq/11) activation alone is sufficient to robustly activate RhoA, the concurrent recruitment of Beta-Arrestin 1 and activation of G(alphaq/11) leads to full activation of RhoA and to the subsequent formation of stress fibers.
Gang Pei - One of the best experts on this subject based on the ideXlab platform.
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Beta-Arrestin signaling and regulation of transcription.
Journal of cell science, 2007Co-Authors: Gang PeiAbstract:Beta-Arrestin 1 and Beta-Arrestin 2 are well-known negative regulators of G-protein-coupled receptor (GPCR) signaling. Upon GPCR activation, Beta-Arrestins translocate to the cell membrane and bind to the agonist-occupied receptors. This uncouples these receptors from G proteins and promotes their internalization, thus causing desensitization. However, accumulating evidence indicates that Beta-Arrestins also function as scaffold proteins that interact with several cytoplasmic proteins and link GPCRs to intracellular signaling pathways such as MAPK cascades. Recent work has also revealed that, in response to activation of certain GPCRs, Beta-Arrestins translocate from the cytoplasm to the nucleus and associate with transcription cofactors such as p300 and cAMP-response element-binding protein (CREB) at the promoters of target genes to promote transcription. They also interact with regulators of transcription factors, such as IkappaBalpha and MDM2, in the cytoplasm and regulate transcription indirectly. This Beta-Arrestin-mediated regulation of transcription appears to play important roles in cell growth, apoptosis and modulation of immune functions.
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Association of Beta-Arrestin and TRAF6 negatively regulates Toll-like receptor-interleukin 1 receptor signaling.
Nature immunology, 2005Co-Authors: Yaya Wang, Yawei Tang, Lin Teng, Xiaohui Zhao, Gang PeiAbstract:Tumor necrosis factor receptor-associated factor 6 (TRAF6) is critical for mediating Toll-like receptor (TLR)-interleukin 1 receptor (IL-1R) signaling and subsequent activation of NF-kappaB and AP-1, transcriptional activators of innate immunity. Here we show that Beta-Arrestins, a family of multifunctional proteins, directly interacted with TRAF6 after TLR-IL-1R activation. Formation of the Beta-Arrestin-TRAF6 complex prevented autoubiquitination of TRAF6 and activation of NF-kappaB and AP-1. Endotoxin-treated Beta-Arrestin 2-deficient mice had higher expression of proinflammatory cytokines and were more susceptible to endotoxic shock. Thus, Beta-Arrestins are essential negative regulators of innate immune activation via TLR-IL-1R signaling.
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Beta-Arrestin 2 functions as a G-protein-coupled receptor-activated regulator of oncoprotein Mdm2.
The Journal of biological chemistry, 2002Co-Authors: Ping Wang, Hua Gao, Beibei Wang, Linhua Qin, Gang PeiAbstract:Oncoprotein Mdm2 is a master negative regulator of the tumor suppressor p53 and has been recently shown to regulate the ubiquitination of Beta-Arrestin 2, an important adapter and scaffold in signaling of G-protein-coupled receptors (GPCRs). However, whether Beta-Arrestin 2 has any effect on the function of Mdm2 is still unclear. Our current results demonstrated that the binding of Mdm2 to Beta-Arrestin 2 was significantly enhanced by stimulation of GPCRs. Activation of GPCRs led to formation of a ternary complex of Mdm2, Beta-Arrestin 2, and GPCRs and thus recruited Mdm2 to GPCRs at plasma membrane. Moreover, the binding of Beta-Arrestin 2 to Mdm2 suppressed the self-ubiquitination of Mdm2 and consequently reduced the Mdm2-mediated p53 degradation and ubiquitination. Further experiments revealed that overexpression of Beta-Arrestin 2 enhanced the p53-mediated apoptosis while suppression of endogenous Beta-Arrestin 2 expression by RNA interference technology considerably attenuated the p53-mediated apoptosis. Our study thus suggests that Beta-Arrestin 2 may serve as a cross-talk linker between GPCR and p53 signaling pathways.
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Beta-Arrestin differentially regulates the chemokine receptor CXCR4-mediated signaling and receptor internalization, and this implicates multiple interaction sites between Beta-Arrestin and CXCR4.
The Journal of biological chemistry, 2000Co-Authors: Zhi-jie Cheng, Jian Zhao, Yue Sun, Bo Cen, Gang PeiAbstract:The chemokine receptor CXCR4 has recently been shown to be a co-receptor involved in the entry of human immunodeficiency virus type 1 into target cells. This study shows that coexpression of Beta-Arrestin with CXCR4 in human embryonic kidney 293 cells attenuated chemokine-stimulated G protein activation and inhibition of cAMP production. Truncation of the C-terminal 34 amino acids of CXCR4 (CXCR4-T) abolished the effects of Beta-Arrestin on CXCR4/G protein signaling, indicating the functional interaction of the receptor C terminus with Beta-Arrestin. On the other hand, receptor internalization and the subsequent activation of extracellular signal-regulated kinases were significantly promoted by coexpression of Beta-Arrestin with CXCR4, whereas the C-terminal truncation of CXCR4 did not affect this regulation of Beta-Arrestin, suggesting that Beta-Arrestin can functionally interact with CXCR4 with or without the C terminus. Moreover, Beta(2)V54D, the dominant inhibitory mutant of Beta-Arrestin 2, exerted no effects on CXCR4/G protein signaling, but strongly influenced receptor internalization and extracellular signal-regulated kinase activation. Further cross-linking experiments demonstrated that Beta-Arrestin as well as Beta(2)V54D could physically contact both CXCR4 and CXCR4-T. Glutathione S-transferase pull-down assay showed that Beta-Arrestin was able to bind efficiently in vitro to both the third intracellular loop and the 34-amino acid C terminus of CXCR4. Taken together, our data clearly establish that Beta-Arrestin can effectively regulate different functions of CXCR4 and that this is mediated through its distinct interactions with the C terminus and other regions including the third loop of CXCR4.
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Selective interference of Beta-Arrestin 1 with kappa and delta but not mu opioid receptor/G protein coupling.
The Journal of biological chemistry, 1998Co-Authors: Zhi-jie Cheng, Gang PeiAbstract:The role of Beta-Arrestin 1 (Beta-arr1) in regulation of responsiveness of kappa, delta, and mu opioid receptors has been investigated in human embryonic kidney 293 cells cotransfected with opioid receptor and Beta-arr1. Expression of human Beta-arr1 attenuated kappa and delta opioid receptor subtype-mediated inhibition of cAMP production and resulted in a 100-fold increase of EC50 values for kappa-agonist U69593 and delta-agonist [D-Pen2, D-Pen5]enkephalin and 30-40% reduction of their maximal responses. In contrast, coexpression of Beta-arr1 with mu opioid receptor did not affect the concentration-effect relationship of mu-agonist [D-Ala2,N-Me-Phe4,Gly5-ol]enkephalin. In parallel, kappa and delta receptor-mediated G protein activation was also remarkably attenuated by overexpression of Beta-arr1, while the mu-agonist-stimulated response remained intact. These results indicate that Beta-arr1 interferes receptor/G protein coupling and differentially regulates the responsiveness of opioid receptors. Truncation of kappa and delta opioid receptors at carboxyl termini abolished inhibition of Beta-arr1 on the responsiveness of both receptors. Furthermore, mu opioid receptor became sensitive to Beta-arr1 regulation following replacement of its carboxyl terminus with the corresponding portion of the delta receptor. Removal of potential phosphorylation sites on the carboxyl terminus of kappa opioid receptor led to reduced effect of Beta-arr1 on the receptor-mediated response. These results suggest that receptor carboxyl terminus and its phosphorylation play an important role in the interaction of Beta-arr1 and opioid receptors.
Eric Reiter - One of the best experts on this subject based on the ideXlab platform.
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Workflow description to dynamically model \Beta-Arrestin signaling networks
arXiv: Molecular Networks, 2018Co-Authors: Romain Yvinec, Mohammed Akli Ayoub, Francesco De Pascali, Pascale Crépieux, Eric Reiter, Anne PouponAbstract:Dynamic models of signaling networks allow the formulation of hypotheses on the topology and kinetic rate laws characterizing a given molecular network, in-depth exploration and confrontation with kinetic biological data. Despite its standardization, dynamic modeling of signaling networks still requires successive technical steps that need to be carefully performed. Here, we detail these steps by going through the mathematical and statistical framework. We explain how it can be applied to the understanding of \Beta-Arrestin-dependent signaling networks. We illustrate our methodology through the modeling of \Beta-Arrestin recruitment kinetics at the Follicle Stimulating Hormone (FSH) receptor supported by in-house Bioluminescence Resonance Energy Transfer (BRET) data.
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Follicle-stimulating hormone (FSH) activates extracellular signal-regulated kinase phosphorylation independently of Beta-Arrestin- and dynamin-mediated FSH receptor internalization.
Reproductive biology and endocrinology : RB&E, 2006Co-Authors: Vincent Piketty, Eric Reiter, Elodie Kara, Florian Guillou, Pascale CrépieuxAbstract:Background The follicle-stimulating hormone receptor (FSH-R) is a seven transmembrane spanning receptor (7TMR) which plays a crucial role in male and female reproduction. Upon FSH stimulation, the FSH-R activates the extracellular signal-regulated kinases (ERK). However, the mechanisms whereby the agonist-stimulated FSH-R activates ERK are poorly understood. In order to activate ERK, some 7 TMRs require Beta-Arrestin-and dynamin-dependent internalization to occur, whereas some others do not. In the present study, we examined the ability of the FSH-activated FSH-R to induce ERK phosphorylation, in conditions where its Beta-Arrestin- and dynamin-mediated internalization was impaired.
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distinct Beta Arrestin and g protein dependent pathways for parathyroid hormone receptor stimulated erk1 2 activation
Journal of Biological Chemistry, 2006Co-Authors: Diane Gestypalmer, Eric Reiter, Minyong Chen, Seungkirl Ahn, Christopher D. Nelson, Shuntai Wang, Allen E. Eckhardt, Conrad L Cowan, Robert F. Spurney, Louis M LuttrellAbstract:Parathyroid hormone (PTH) regulates calcium homeostasis via the type I PTH/PTH-related peptide (PTH/PTHrP) receptor (PTH1R). The purpose of the present study was to identify the contributions of distinct signaling mechanisms to PTH-stimulated activation of the mitogen-activated protein kinases (MAPK) ERK1/2. In Human embryonic kidney 293 (HEK293) cells transiently transfected with hPTH1R, PTH stimulated a robust increase in ERK activity. The time course of ERK1/2 activation was biphasic with an early peak at 10 min and a later sustained ERK1/2 activation persisting for greater than 60 min. Pretreatment of HEK293 cells with the PKA inhibitor H89 or the PKC inhibitor GF109203X, individually or in combination reduced the early component of PTH-stimulated ERK activity. However, these inhibitors of second messenger dependent kinases had little effect on the later phase of PTH-stimulated ERK1/2 phosphorylation. This later phase of ERK1/2 activation at 30-60 min was blocked by depletion of cellular Beta-Arrestin 2 and Beta-Arrestin 1 by small interfering RNA. Furthermore, stimulation of hPTH1R with PTH analogues, [Trp1]PTHrp-(1-36) and [d-Trp12,Tyr34]PTH-(7-34), selectively activated G(s)/PKA-mediated ERK1/2 activation or G protein-independent/Beta-Arrestin-dependent ERK1/2 activation, respectively. It is concluded that PTH stimulates ERK1/2 through several distinct signal transduction pathways: an early G protein-dependent pathway meditated by PKA and PKC and a late pathway independent of G proteins mediated through Beta-Arrestins. These findings imply the existence of distinct active conformations of the hPTH1R responsible for the two pathways, which can be stimulated by unique ligands. Such ligands may have distinct and valuable therapeutic properties.
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Distinct Beta-Arrestin- and G protein-dependent pathways for parathyroid hormone receptor-stimulated ERK1/2 activation.
The Journal of biological chemistry, 2006Co-Authors: Diane Gesty-palmer, Eric Reiter, Minyong Chen, Seungkirl Ahn, Christopher D. Nelson, Shuntai Wang, Allen E. Eckhardt, Conrad L Cowan, Robert F. Spurney, Louis M LuttrellAbstract:Parathyroid hormone (PTH) regulates calcium homeostasis via the type I PTH/PTH-related peptide (PTH/PTHrP) receptor (PTH1R). The purpose of the present study was to identify the contributions of distinct signaling mechanisms to PTH-stimulated activation of the mitogen-activated protein kinases (MAPK) ERK1/2. In Human embryonic kidney 293 (HEK293) cells transiently transfected with hPTH1R, PTH stimulated a robust increase in ERK activity. The time course of ERK1/2 activation was biphasic with an early peak at 10 min and a later sustained ERK1/2 activation persisting for greater than 60 min. Pretreatment of HEK293 cells with the PKA inhibitor H89 or the PKC inhibitor GF109203X, individually or in combination reduced the early component of PTH-stimulated ERK activity. However, these inhibitors of second messenger dependent kinases had little effect on the later phase of PTH-stimulated ERK1/2 phosphorylation. This later phase of ERK1/2 activation at 30-60 min was blocked by depletion of cellular Beta-Arrestin 2 and Beta-Arrestin 1 by small interfering RNA. Furthermore, stimulation of hPTH1R with PTH analogues, [Trp1]PTHrp-(1-36) and [d-Trp12,Tyr34]PTH-(7-34), selectively activated G(s)/PKA-mediated ERK1/2 activation or G protein-independent/Beta-Arrestin-dependent ERK1/2 activation, respectively. It is concluded that PTH stimulates ERK1/2 through several distinct signal transduction pathways: an early G protein-dependent pathway meditated by PKA and PKC and a late pathway independent of G proteins mediated through Beta-Arrestins. These findings imply the existence of distinct active conformations of the hPTH1R responsible for the two pathways, which can be stimulated by unique ligands. Such ligands may have distinct and valuable therapeutic properties.
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Follicle-stimulating hormone (FSH) activates extracellular signal-regulated kinase phosphorylation independently of Beta-Arrestin- and dynamin-mediated FSH receptor internalization
Reproductive Biology and Endocrinology, 2006Co-Authors: Vincent Piketty, Eric Reiter, Elodie Kara, Florian Jean Louis Guillou, Pascale CrépieuxAbstract:BACKGROUND: The follicle-stimulating hormone receptor (FSH-R) is a seven transmembrane spanning receptor (7TMR) which plays a crucial role in male and female reproduction. Upon FSH stimulation, the FSH-R activates the extracellular signal-regulated kinases (ERK). However, the mechanisms whereby the agonist-stimulated FSH-R activates ERK are poorly understood. In order to activate ERK, some 7 TMRs require Beta-Arrestin-and dynamin-dependent internalization to occur, whereas some others do not. In the present study, we examined the ability of the FSH-activated FSH-R to induce ERK phosphorylation, in conditions where its Beta-Arrestin- and dynamin-mediated internalization was impaired. METHODS: Human embryonic kidney (HEK) 293 cells were transiently transfected with the rat FSH-R. Internalization of the FSH-R was manipulated by co-expression of either a Beta-Arrestin (319-418) dominant negative peptide, either an inactive dynamin K44A mutant or of wild-type Beta-Arrestin 1 or 2. The outcomes on the FSH-R internalization were assayed by measuring 125I-FSH binding at the cell surface when compared to internalized 125I-FSH binding. The resulting ERK phosphorylation level was visualized by Western blot analysis. RESULTS: In HEK 293 cells, FSH stimulated ERK phosphorylation in a dose-dependent manner. Co-transfection of the Beta- Arrestin (319-418) construct, or of the dynamin K44A mutant reduced FSH-R internalization in response to FSH, without affecting ERK phosphorylation. Likewise, overexpression of wild-type Beta-Arrestin 1 or 2 significantly increased the FSH-R internalization level in response to FSH, without altering FSH-induced ERK phosphorylation. CONCLUSION: From these results, we conclude that the FSH-R does not require Beta-Arrestin- nor dynamin-mediated internalization to initiate ERK phosphorylation in response to FSH.