The Experts below are selected from a list of 21579 Experts worldwide ranked by ideXlab platform
J. Dubuisson - One of the best experts on this subject based on the ideXlab platform.
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Transmembrane domains of hepatitis C virus envelope glycoproteins: residues involved in E1E2 Heterodimerization and involvement of these domains in virus entry.
Journal of Virology, 2007Co-Authors: Y. Ciczora, N. Callens, F. Penin, Ei Pecheur, J. DubuissonAbstract:The transmembrane (TM) domains of hepatitis C virus (HCV) envelope glycoproteins E1 and E2 have been shown to play multiple roles during the biogenesis of the E1E2 heterodimer. By using alanine scanning insertion mutagenesis within the TM domains of HCV envelope glycoproteins, we have previously shown that the central regions of these domains as well as the N-terminal part of the TM domain of E1 are involved in Heterodimerization. Here, we used a tryptophan replacement scan of these regions to identify individual residues that participate in those interactions. Our mutagenesis study identified at least four residues involved in Heterodimerization: Gly 354, Gly 358, Lys 370, and Asp 728. Interestingly, Gly 354 and Gly 358 belong to a GXXXG oligomerization motif. Our tryptophan mutants were also used to generate retrovirus-based, HCV-pseudotyped particles (HCVpp) in order to analyze the effects of these mutations on virus entry. Surprisingly, two mutants consistently displayed higher infectivity compared to that of the wild type. In contrast, HCVpp infectivity was strongly affected for many mutants, despite normal E1E2 Heterodimerization and normal levels of incorporation of HCV glycoproteins into HCVpp. The characterization of some of these HCVpp mutants in the recently developed in vitro fusion assay using fluorescent-labeled liposomes indicated that mutations reducing HCVpp infectivity without altering E1E2 Heterodimerization affected the fusion properties of HCV envelope glycoproteins. In conclusion, this mutational analysis identified residues involved in E1E2 Heterodimerization and revealed that the TM domains of HCV envelope glycoproteins play a major role in the fusion properties of these proteins.The transmembrane (TM) domains of hepatitis C virus (HCV) envelope glycoproteins E1 and E2 have been shown to play multiple roles during the biogenesis of the E1E2 heterodimer. By using alanine scanning insertion mutagenesis within the TM domains of HCV envelope glycoproteins, we have previously shown that the central regions of these domains as well as the N-terminal part of the TM domain of E1 are involved in Heterodimerization. Here, we used a tryptophan replacement scan of these regions to identify individual residues that participate in those interactions. Our mutagenesis study identified at least four residues involved in Heterodimerization: Gly 354, Gly 358, Lys 370, and Asp 728. Interestingly, Gly 354 and Gly 358 belong to a GXXXG oligomerization motif. Our tryptophan mutants were also used to generate retrovirus-based, HCV-pseudotyped particles (HCVpp) in order to analyze the effects of these mutations on virus entry. Surprisingly, two mutants consistently displayed higher infectivity compared to that of the wild type. In contrast, HCVpp infectivity was strongly affected for many mutants, despite normal E1E2 Heterodimerization and normal levels of incorporation of HCV glycoproteins into HCVpp. The characterization of some of these HCVpp mutants in the recently developed in vitro fusion assay using fluorescent-labeled liposomes indicated that mutations reducing HCVpp infectivity without altering E1E2 Heterodimerization affected the fusion properties of HCV envelope glycoproteins. In conclusion, this mutational analysis identified residues involved in E1E2 Heterodimerization and revealed that the TM domains of HCV envelope glycoproteins play a major role in the fusion properties of these proteins.
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The transmembrane domains of HCV envelope glycoproteins: residues involved in E1E2 Heterodimerization and involvement of these domains in virus entry.
Journal of Virology, 2007Co-Authors: Y. Ciczora, N. Callens, F. Penin, Ei Pecheur, J. DubuissonAbstract:The transmembrane (TM) domains of hepatitis C virus (HCV) envelope glycoproteins E1 and E2 have been shown to play multiple roles during the biogenesis of the E1E2 heterodimer. By using alanine scanning insertion mutagenesis within the TM domains of HCV envelope glycoproteins, we have previously shown that the central regions of these domains as well as the N-terminal part of the TM domain of E1 are involved in Heterodimerization. Here, we used a tryptophan replacement scan of these regions to identify individual residues that participate in those interactions. Our mutagenesis study identified at least four residues involved in Heterodimerization: Gly 354, Gly 358, Lys 370, and Asp 728. Interestingly, Gly 354 and Gly 358 belong to a GXXXG oligomerization motif. Our tryptophan mutants were also used to generate retrovirus-based, HCV-pseudotyped particles (HCVpp) in order to analyze the effects of these mutations on virus entry. Surprisingly, two mutants consistently displayed higher infectivity compared to that of the wild type. In contrast, HCVpp infectivity was strongly affected for many mutants, despite normal E1E2 Heterodimerization and normal levels of incorporation of HCV glycoproteins into HCVpp. The characterization of some of these HCVpp mutants in the recently developed in vitro fusion assay using fluorescent-labeled liposomes indicated that mutations reducing HCVpp infectivity without altering E1E2 Heterodimerization affected the fusion properties of HCV envelope glycoproteins. In conclusion, this mutational analysis identified residues involved in E1E2 Heterodimerization and revealed that the TM domains of HCV envelope glycoproteins play a major role in the fusion properties of these proteins.
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Transmembrane Domains of Hepatitis C Virus Envelope Glycoproteins: Residues Involved in E1E2 Heterodimerization and Involvement of These Domains in Virus Entry
Journal of virology, 2006Co-Authors: Y. Ciczora, N. Callens, F. Penin, Ei Pecheur, J. DubuissonAbstract:The transmembrane (TM) domains of hepatitis C virus (HCV) envelope glycoproteins E1 and E2 have been shown to play multiple roles during the biogenesis of the E1E2 heterodimer. By using alanine scanning insertion mutagenesis within the TM domains of HCV envelope glycoproteins, we have previously shown that the central regions of these domains as well as the N-terminal part of the TM domain of E1 are involved in Heterodimerization. Here, we used a tryptophan replacement scan of these regions to identify individual residues that participate in those interactions. Our mutagenesis study identified at least four residues involved in Heterodimerization: Gly 354, Gly 358, Lys 370, and Asp 728. Interestingly, Gly 354 and Gly 358 belong to a GXXXG oligomerization motif. Our tryptophan mutants were also used to generate retrovirus-based, HCV-pseudotyped particles (HCVpp) in order to analyze the effects of these mutations on virus entry. Surprisingly, two mutants consistently displayed higher infectivity compared to that of the wild type. In contrast, HCVpp infectivity was strongly affected for many mutants, despite normal E1E2 Heterodimerization and normal levels of incorporation of HCV glycoproteins into HCVpp. The characterization of some of these HCVpp mutants in the recently developed in vitro fusion assay using fluorescent-labeled liposomes indicated that mutations reducing HCVpp infectivity without altering E1E2 Heterodimerization affected the fusion properties of HCV envelope glycoproteins. In conclusion, this mutational analysis identified residues involved in E1E2 Heterodimerization and revealed that the TM domains of HCV envelope glycoproteins play a major role in the fusion properties of these proteins.
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The transmembrane domains of hepatitis C virus envelope glycoproteins E1 and E2 play a major role in Heterodimerization.
The Journal of biological chemistry, 2000Co-Authors: A. Op De Beeck, F. Penin, R. Montserret, Sandrine Duvet, Laurence Cocquerel, René Cacan, B Barberot, M. Le Maire, J. DubuissonAbstract:Oligomerization of viral envelope proteins is essential to control virus assembly and fusion. The transmembrane domains (TMDs) of hepatitis C virus envelope glycoproteins E1 and E2 have been shown to play multiple functions during the biogenesis of E1E2 heterodimer. This makes them very unique among known transmembrane sequences. In this report, we used alanine scanning insertion mutagenesis in the TMDs of E1 and E2 to examine their role in the assembly of E1E2 heterodimer. Alanine insertion within the center of the TMDs of E1 or E2 or in the N-terminal part of the TMD of E1 dramatically reduced Heterodimerization, demonstrating the essential role played by these domains in the assembly of hepatitis C virus envelope glycoproteins. To better understand the alanine scanning data obtained for the TMD of E1 which contains GXXXG motifs, we analyzed by circular dichroism and nuclear magnetic resonance the three-dimensional structure of the E1-(350-370) peptide encompassing the N-terminal sequence of the TMD of E1 involved in Heterodimerization. Alanine scanning results and the three-dimensional molecular model we obtained provide the first framework for a molecular level understanding of the mechanism of hepatitis C virus envelope glycoprotein Heterodimerization.
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The transmembrane domains of hepatitis C virus envelope glycoproteins E1 and E2 play a major role in Heterodimerization.
Journal of Biological Chemistry, 2000Co-Authors: A. Opdebeeck, F. Penin, R. Montserret, Sandrine Duvet, Laurence Cocquerel, René Cacan, B Barberot, M. Lemaire, J. DubuissonAbstract:Oligomerization of viral envelope proteins is essential to control virus assembly and fusion. The transmembrane domains (TMDs) of hepatitis C virus envelope glycoproteins E1 and E2 have been shown to play multiple functions during the biogenesis of E1E2 heterodimer. This makes them very unique among known transmembrane sequences. In this report, we used alanine scanning insertion mutagenesis in the TMDs of E1 and E2 to examine their role in the assembly of E1E2 heterodimer. Alanine insertion within the center of the TMDs of E1 or E2 or in the N-terminal part of the TMD of E1 dramatically reduced Heterodimerization, demonstrating the essential role played by these domains in the assembly of hepatitis C virus envelope glycoproteins. To better understand the alanine scanning data obtained for the TMD of E1 which contains GXXXG motifs, we analyzed by circular dichroism and nuclear magnetic resonance the three-dimensional structure of the E1-(350-370) peptide encompassing the N-terminal sequence of the TMD of E1 involved in Heterodimerization. Alanine scanning results and the three-dimensional molecular model we obtained provide the first framework for a molecular level understanding of the mechanism of hepatitis C virus envelope glycoprotein Heterodimerization.Oligomerization of viral envelope proteins is essential to control virus assembly and fusion. The transmembrane domains (TMDs) of hepatitis C virus envelope glycoproteins E1 and E2 have been shown to play multiple functions during the biogenesis of E1E2 heterodimer. This makes them very unique among known transmembrane sequences. In this report, we used alanine scanning insertion mutagenesis in the TMDs of E1 and E2 to examine their role in the assembly of E1E2 heterodimer. Alanine insertion within the center of the TMDs of E1 or E2 or in the N-terminal part of the TMD of E1 dramatically reduced Heterodimerization, demonstrating the essential role played by these domains in the assembly of hepatitis C virus envelope glycoproteins. To better understand the alanine scanning data obtained for the TMD of E1 which contains GXXXG motifs, we analyzed by circular dichroism and nuclear magnetic resonance the three-dimensional structure of the E1-(350-370) peptide encompassing the N-terminal sequence of the TMD of E1 involved in Heterodimerization. Alanine scanning results and the three-dimensional molecular model we obtained provide the first framework for a molecular level understanding of the mechanism of hepatitis C virus envelope glycoprotein Heterodimerization.
Jing Chen - One of the best experts on this subject based on the ideXlab platform.
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Heterodimerization of human orexin receptor 1 and kappa opioid receptor promotes protein kinase a camp response element binding protein signaling via a gαs mediated mechanism
Cellular Signalling, 2015Co-Authors: Yunlu Jiang, Xin Cai, Jing Chen, Rumin Zhang, Xiaoyu Chen, Chunmei Wang, Haiqing Liu, Chuanxin Liu, Bo BaiAbstract:Orexin and dynorphin are co-expressed in the same synaptic vesicles of hypothalamic neurons and play opposing roles in cocaine self-administration, brain stimulation reward, and impulsivity in ventral tegmental area (VTA), where dopamine neurons express both OX1R and KORs. However, detailed mechanisms of how the coreleased peptides and both receptors fine-tune their signalings and physiological/behavioral effects together remain unclear. Here we explore the possibility of Heterodimerization between OX1R and KOR and reveal novel signal transduction mechanisms. First, we demonstrated co-expression of OX1R and KOR in rat hippocampal neurons by single-cell PCR. Furthermore, Heterodimerization between OX1R and KOR was examined using bioluminescence and fluorescence resonance energy transfer (BRET and FRET). Our data revealed that human OX1R and KOR heterodimerize, and this heterodimer associates with Gαs, leading to increased protein kinase A (PKA) signaling pathway activity, including upregulation of intracellular cAMP levels and cAMP-response element (CRE) luciferase reporter activity, resulting in increased cAMP-response element binding protein (CREB) phosphorylation. These results support the view that OX1R and KOR Heterodimerization might have an anti-depressive role.
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Heterodimerization of apelin receptor and neurotensin receptor 1 induces phosphorylation of erk1 2 and cell proliferation via gαq mediated mechanism
Journal of Cellular and Molecular Medicine, 2014Co-Authors: Bo Bai, Yunlu Jiang, Xin Cai, Jing Chen, Emmanouil KarterisAbstract:Dimerization of G protein-coupled receptors (GPCRs) is crucial for receptor function including agonist affinity, efficacy, trafficking and specificity of signal transduction, including G protein coupling. Emerging data suggest that the cardiovascular system is the main target of apelin, which exerts an overall neuroprotective role, and is a positive regulator of angiotensin-converting enzyme 2 (ACE2) in heart failure. Moreover, ACE2 cleaves off C-terminal residues of vasoactive peptides including apelin-13, and neurotensin that activate the apelin receptor (APJ) and neurotensin receptor 1 (NTSR1) respectively, that belong to the A class of GPCRs. Therefore, based on the similar mode of modification by ACE2 at peptide level, the homology at amino acid level and the capability of forming dimers with other GPCRs, we have been suggested that APJ and NTSR1 can form a functional heterodimer. Using co-immunoprecipitation, BRET and FRET, we provided conclusive evidence of Heterodimerization between APJ and NTSR1 in a constitutive and induced form. Upon agonist stimulation, hetrodimerization enhanced ERK1/2 activation and increased proliferation via activation of Gq α-subunits. These novel data provide evidence for a physiological role of APJ/NTSR1 heterodimers in terms of ERK1/2 activation and increased intracellular calcium and induced cell proliferation and provide potential new pharmaceutical targets for cardiovascular disease.
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Heterodimerization of apelin receptor and neurotensin receptor 1 induces phosphorylation of ERK1/2 and cell proliferation via Gαq-mediated mechanism
Journal of cellular and molecular medicine, 2014Co-Authors: Bo Bai, Yunlu Jiang, Xin Cai, Emmanouil Karteris, Jing ChenAbstract:Dimerization of G protein-coupled receptors (GPCRs) is crucial for receptor function including agonist affinity, efficacy, trafficking and specificity of signal transduction, including G protein coupling. Emerging data suggest that the cardiovascular system is the main target of apelin, which exerts an overall neuroprotective role, and is a positive regulator of angiotensin-converting enzyme 2 (ACE2) in heart failure. Moreover, ACE2 cleaves off C-terminal residues of vasoactive peptides including apelin-13, and neurotensin that activate the apelin receptor (APJ) and neurotensin receptor 1 (NTSR1) respectively, that belong to the A class of GPCRs. Therefore, based on the similar mode of modification by ACE2 at peptide level, the homology at amino acid level and the capability of forming dimers with other GPCRs, we have been suggested that APJ and NTSR1 can form a functional heterodimer. Using co-immunoprecipitation, BRET and FRET, we provided conclusive evidence of Heterodimerization between APJ and NTSR1 in a constitutive and induced form. Upon agonist stimulation, hetrodimerization enhanced ERK1/2 activation and increased proliferation via activation of Gq α-subunits. These novel data provide evidence for a physiological role of APJ/NTSR1 heterodimers in terms of ERK1/2 activation and increased intracellular calcium and induced cell proliferation and provide potential new pharmaceutical targets for cardiovascular disease.
F. Penin - One of the best experts on this subject based on the ideXlab platform.
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Transmembrane domains of hepatitis C virus envelope glycoproteins: residues involved in E1E2 Heterodimerization and involvement of these domains in virus entry.
Journal of Virology, 2007Co-Authors: Y. Ciczora, N. Callens, F. Penin, Ei Pecheur, J. DubuissonAbstract:The transmembrane (TM) domains of hepatitis C virus (HCV) envelope glycoproteins E1 and E2 have been shown to play multiple roles during the biogenesis of the E1E2 heterodimer. By using alanine scanning insertion mutagenesis within the TM domains of HCV envelope glycoproteins, we have previously shown that the central regions of these domains as well as the N-terminal part of the TM domain of E1 are involved in Heterodimerization. Here, we used a tryptophan replacement scan of these regions to identify individual residues that participate in those interactions. Our mutagenesis study identified at least four residues involved in Heterodimerization: Gly 354, Gly 358, Lys 370, and Asp 728. Interestingly, Gly 354 and Gly 358 belong to a GXXXG oligomerization motif. Our tryptophan mutants were also used to generate retrovirus-based, HCV-pseudotyped particles (HCVpp) in order to analyze the effects of these mutations on virus entry. Surprisingly, two mutants consistently displayed higher infectivity compared to that of the wild type. In contrast, HCVpp infectivity was strongly affected for many mutants, despite normal E1E2 Heterodimerization and normal levels of incorporation of HCV glycoproteins into HCVpp. The characterization of some of these HCVpp mutants in the recently developed in vitro fusion assay using fluorescent-labeled liposomes indicated that mutations reducing HCVpp infectivity without altering E1E2 Heterodimerization affected the fusion properties of HCV envelope glycoproteins. In conclusion, this mutational analysis identified residues involved in E1E2 Heterodimerization and revealed that the TM domains of HCV envelope glycoproteins play a major role in the fusion properties of these proteins.The transmembrane (TM) domains of hepatitis C virus (HCV) envelope glycoproteins E1 and E2 have been shown to play multiple roles during the biogenesis of the E1E2 heterodimer. By using alanine scanning insertion mutagenesis within the TM domains of HCV envelope glycoproteins, we have previously shown that the central regions of these domains as well as the N-terminal part of the TM domain of E1 are involved in Heterodimerization. Here, we used a tryptophan replacement scan of these regions to identify individual residues that participate in those interactions. Our mutagenesis study identified at least four residues involved in Heterodimerization: Gly 354, Gly 358, Lys 370, and Asp 728. Interestingly, Gly 354 and Gly 358 belong to a GXXXG oligomerization motif. Our tryptophan mutants were also used to generate retrovirus-based, HCV-pseudotyped particles (HCVpp) in order to analyze the effects of these mutations on virus entry. Surprisingly, two mutants consistently displayed higher infectivity compared to that of the wild type. In contrast, HCVpp infectivity was strongly affected for many mutants, despite normal E1E2 Heterodimerization and normal levels of incorporation of HCV glycoproteins into HCVpp. The characterization of some of these HCVpp mutants in the recently developed in vitro fusion assay using fluorescent-labeled liposomes indicated that mutations reducing HCVpp infectivity without altering E1E2 Heterodimerization affected the fusion properties of HCV envelope glycoproteins. In conclusion, this mutational analysis identified residues involved in E1E2 Heterodimerization and revealed that the TM domains of HCV envelope glycoproteins play a major role in the fusion properties of these proteins.
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The transmembrane domains of HCV envelope glycoproteins: residues involved in E1E2 Heterodimerization and involvement of these domains in virus entry.
Journal of Virology, 2007Co-Authors: Y. Ciczora, N. Callens, F. Penin, Ei Pecheur, J. DubuissonAbstract:The transmembrane (TM) domains of hepatitis C virus (HCV) envelope glycoproteins E1 and E2 have been shown to play multiple roles during the biogenesis of the E1E2 heterodimer. By using alanine scanning insertion mutagenesis within the TM domains of HCV envelope glycoproteins, we have previously shown that the central regions of these domains as well as the N-terminal part of the TM domain of E1 are involved in Heterodimerization. Here, we used a tryptophan replacement scan of these regions to identify individual residues that participate in those interactions. Our mutagenesis study identified at least four residues involved in Heterodimerization: Gly 354, Gly 358, Lys 370, and Asp 728. Interestingly, Gly 354 and Gly 358 belong to a GXXXG oligomerization motif. Our tryptophan mutants were also used to generate retrovirus-based, HCV-pseudotyped particles (HCVpp) in order to analyze the effects of these mutations on virus entry. Surprisingly, two mutants consistently displayed higher infectivity compared to that of the wild type. In contrast, HCVpp infectivity was strongly affected for many mutants, despite normal E1E2 Heterodimerization and normal levels of incorporation of HCV glycoproteins into HCVpp. The characterization of some of these HCVpp mutants in the recently developed in vitro fusion assay using fluorescent-labeled liposomes indicated that mutations reducing HCVpp infectivity without altering E1E2 Heterodimerization affected the fusion properties of HCV envelope glycoproteins. In conclusion, this mutational analysis identified residues involved in E1E2 Heterodimerization and revealed that the TM domains of HCV envelope glycoproteins play a major role in the fusion properties of these proteins.
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Transmembrane Domains of Hepatitis C Virus Envelope Glycoproteins: Residues Involved in E1E2 Heterodimerization and Involvement of These Domains in Virus Entry
Journal of virology, 2006Co-Authors: Y. Ciczora, N. Callens, F. Penin, Ei Pecheur, J. DubuissonAbstract:The transmembrane (TM) domains of hepatitis C virus (HCV) envelope glycoproteins E1 and E2 have been shown to play multiple roles during the biogenesis of the E1E2 heterodimer. By using alanine scanning insertion mutagenesis within the TM domains of HCV envelope glycoproteins, we have previously shown that the central regions of these domains as well as the N-terminal part of the TM domain of E1 are involved in Heterodimerization. Here, we used a tryptophan replacement scan of these regions to identify individual residues that participate in those interactions. Our mutagenesis study identified at least four residues involved in Heterodimerization: Gly 354, Gly 358, Lys 370, and Asp 728. Interestingly, Gly 354 and Gly 358 belong to a GXXXG oligomerization motif. Our tryptophan mutants were also used to generate retrovirus-based, HCV-pseudotyped particles (HCVpp) in order to analyze the effects of these mutations on virus entry. Surprisingly, two mutants consistently displayed higher infectivity compared to that of the wild type. In contrast, HCVpp infectivity was strongly affected for many mutants, despite normal E1E2 Heterodimerization and normal levels of incorporation of HCV glycoproteins into HCVpp. The characterization of some of these HCVpp mutants in the recently developed in vitro fusion assay using fluorescent-labeled liposomes indicated that mutations reducing HCVpp infectivity without altering E1E2 Heterodimerization affected the fusion properties of HCV envelope glycoproteins. In conclusion, this mutational analysis identified residues involved in E1E2 Heterodimerization and revealed that the TM domains of HCV envelope glycoproteins play a major role in the fusion properties of these proteins.
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The transmembrane domains of hepatitis C virus envelope glycoproteins E1 and E2 play a major role in Heterodimerization.
The Journal of biological chemistry, 2000Co-Authors: A. Op De Beeck, F. Penin, R. Montserret, Sandrine Duvet, Laurence Cocquerel, René Cacan, B Barberot, M. Le Maire, J. DubuissonAbstract:Oligomerization of viral envelope proteins is essential to control virus assembly and fusion. The transmembrane domains (TMDs) of hepatitis C virus envelope glycoproteins E1 and E2 have been shown to play multiple functions during the biogenesis of E1E2 heterodimer. This makes them very unique among known transmembrane sequences. In this report, we used alanine scanning insertion mutagenesis in the TMDs of E1 and E2 to examine their role in the assembly of E1E2 heterodimer. Alanine insertion within the center of the TMDs of E1 or E2 or in the N-terminal part of the TMD of E1 dramatically reduced Heterodimerization, demonstrating the essential role played by these domains in the assembly of hepatitis C virus envelope glycoproteins. To better understand the alanine scanning data obtained for the TMD of E1 which contains GXXXG motifs, we analyzed by circular dichroism and nuclear magnetic resonance the three-dimensional structure of the E1-(350-370) peptide encompassing the N-terminal sequence of the TMD of E1 involved in Heterodimerization. Alanine scanning results and the three-dimensional molecular model we obtained provide the first framework for a molecular level understanding of the mechanism of hepatitis C virus envelope glycoprotein Heterodimerization.
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The transmembrane domains of hepatitis C virus envelope glycoproteins E1 and E2 play a major role in Heterodimerization.
Journal of Biological Chemistry, 2000Co-Authors: A. Opdebeeck, F. Penin, R. Montserret, Sandrine Duvet, Laurence Cocquerel, René Cacan, B Barberot, M. Lemaire, J. DubuissonAbstract:Oligomerization of viral envelope proteins is essential to control virus assembly and fusion. The transmembrane domains (TMDs) of hepatitis C virus envelope glycoproteins E1 and E2 have been shown to play multiple functions during the biogenesis of E1E2 heterodimer. This makes them very unique among known transmembrane sequences. In this report, we used alanine scanning insertion mutagenesis in the TMDs of E1 and E2 to examine their role in the assembly of E1E2 heterodimer. Alanine insertion within the center of the TMDs of E1 or E2 or in the N-terminal part of the TMD of E1 dramatically reduced Heterodimerization, demonstrating the essential role played by these domains in the assembly of hepatitis C virus envelope glycoproteins. To better understand the alanine scanning data obtained for the TMD of E1 which contains GXXXG motifs, we analyzed by circular dichroism and nuclear magnetic resonance the three-dimensional structure of the E1-(350-370) peptide encompassing the N-terminal sequence of the TMD of E1 involved in Heterodimerization. Alanine scanning results and the three-dimensional molecular model we obtained provide the first framework for a molecular level understanding of the mechanism of hepatitis C virus envelope glycoprotein Heterodimerization.Oligomerization of viral envelope proteins is essential to control virus assembly and fusion. The transmembrane domains (TMDs) of hepatitis C virus envelope glycoproteins E1 and E2 have been shown to play multiple functions during the biogenesis of E1E2 heterodimer. This makes them very unique among known transmembrane sequences. In this report, we used alanine scanning insertion mutagenesis in the TMDs of E1 and E2 to examine their role in the assembly of E1E2 heterodimer. Alanine insertion within the center of the TMDs of E1 or E2 or in the N-terminal part of the TMD of E1 dramatically reduced Heterodimerization, demonstrating the essential role played by these domains in the assembly of hepatitis C virus envelope glycoproteins. To better understand the alanine scanning data obtained for the TMD of E1 which contains GXXXG motifs, we analyzed by circular dichroism and nuclear magnetic resonance the three-dimensional structure of the E1-(350-370) peptide encompassing the N-terminal sequence of the TMD of E1 involved in Heterodimerization. Alanine scanning results and the three-dimensional molecular model we obtained provide the first framework for a molecular level understanding of the mechanism of hepatitis C virus envelope glycoprotein Heterodimerization.
Bo Bai - One of the best experts on this subject based on the ideXlab platform.
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Heterodimerization of human orexin receptor 1 and kappa opioid receptor promotes protein kinase a camp response element binding protein signaling via a gαs mediated mechanism
Cellular Signalling, 2015Co-Authors: Yunlu Jiang, Xin Cai, Jing Chen, Rumin Zhang, Xiaoyu Chen, Chunmei Wang, Haiqing Liu, Chuanxin Liu, Bo BaiAbstract:Orexin and dynorphin are co-expressed in the same synaptic vesicles of hypothalamic neurons and play opposing roles in cocaine self-administration, brain stimulation reward, and impulsivity in ventral tegmental area (VTA), where dopamine neurons express both OX1R and KORs. However, detailed mechanisms of how the coreleased peptides and both receptors fine-tune their signalings and physiological/behavioral effects together remain unclear. Here we explore the possibility of Heterodimerization between OX1R and KOR and reveal novel signal transduction mechanisms. First, we demonstrated co-expression of OX1R and KOR in rat hippocampal neurons by single-cell PCR. Furthermore, Heterodimerization between OX1R and KOR was examined using bioluminescence and fluorescence resonance energy transfer (BRET and FRET). Our data revealed that human OX1R and KOR heterodimerize, and this heterodimer associates with Gαs, leading to increased protein kinase A (PKA) signaling pathway activity, including upregulation of intracellular cAMP levels and cAMP-response element (CRE) luciferase reporter activity, resulting in increased cAMP-response element binding protein (CREB) phosphorylation. These results support the view that OX1R and KOR Heterodimerization might have an anti-depressive role.
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Heterodimerization of apelin receptor and neurotensin receptor 1 induces phosphorylation of erk1 2 and cell proliferation via gαq mediated mechanism
Journal of Cellular and Molecular Medicine, 2014Co-Authors: Bo Bai, Yunlu Jiang, Xin Cai, Jing Chen, Emmanouil KarterisAbstract:Dimerization of G protein-coupled receptors (GPCRs) is crucial for receptor function including agonist affinity, efficacy, trafficking and specificity of signal transduction, including G protein coupling. Emerging data suggest that the cardiovascular system is the main target of apelin, which exerts an overall neuroprotective role, and is a positive regulator of angiotensin-converting enzyme 2 (ACE2) in heart failure. Moreover, ACE2 cleaves off C-terminal residues of vasoactive peptides including apelin-13, and neurotensin that activate the apelin receptor (APJ) and neurotensin receptor 1 (NTSR1) respectively, that belong to the A class of GPCRs. Therefore, based on the similar mode of modification by ACE2 at peptide level, the homology at amino acid level and the capability of forming dimers with other GPCRs, we have been suggested that APJ and NTSR1 can form a functional heterodimer. Using co-immunoprecipitation, BRET and FRET, we provided conclusive evidence of Heterodimerization between APJ and NTSR1 in a constitutive and induced form. Upon agonist stimulation, hetrodimerization enhanced ERK1/2 activation and increased proliferation via activation of Gq α-subunits. These novel data provide evidence for a physiological role of APJ/NTSR1 heterodimers in terms of ERK1/2 activation and increased intracellular calcium and induced cell proliferation and provide potential new pharmaceutical targets for cardiovascular disease.
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Heterodimerization of apelin receptor and neurotensin receptor 1 induces phosphorylation of ERK1/2 and cell proliferation via Gαq-mediated mechanism
Journal of cellular and molecular medicine, 2014Co-Authors: Bo Bai, Yunlu Jiang, Xin Cai, Emmanouil Karteris, Jing ChenAbstract:Dimerization of G protein-coupled receptors (GPCRs) is crucial for receptor function including agonist affinity, efficacy, trafficking and specificity of signal transduction, including G protein coupling. Emerging data suggest that the cardiovascular system is the main target of apelin, which exerts an overall neuroprotective role, and is a positive regulator of angiotensin-converting enzyme 2 (ACE2) in heart failure. Moreover, ACE2 cleaves off C-terminal residues of vasoactive peptides including apelin-13, and neurotensin that activate the apelin receptor (APJ) and neurotensin receptor 1 (NTSR1) respectively, that belong to the A class of GPCRs. Therefore, based on the similar mode of modification by ACE2 at peptide level, the homology at amino acid level and the capability of forming dimers with other GPCRs, we have been suggested that APJ and NTSR1 can form a functional heterodimer. Using co-immunoprecipitation, BRET and FRET, we provided conclusive evidence of Heterodimerization between APJ and NTSR1 in a constitutive and induced form. Upon agonist stimulation, hetrodimerization enhanced ERK1/2 activation and increased proliferation via activation of Gq α-subunits. These novel data provide evidence for a physiological role of APJ/NTSR1 heterodimers in terms of ERK1/2 activation and increased intracellular calcium and induced cell proliferation and provide potential new pharmaceutical targets for cardiovascular disease.
Ujendra Kumar - One of the best experts on this subject based on the ideXlab platform.
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Coexpression of human somatostatin receptor-2 (SSTR2) and SSTR3 modulates antiproliferative signaling and apoptosis
Journal of molecular signaling, 2012Co-Authors: Sajad A. War, Ujendra KumarAbstract:Background Somatostatin (SST) via five Gi coupled receptors namely SSTR1-5 is known to inhibit cell proliferation by cytostatic and cytotoxic mechanisms. Heterodimerization plays a crucial role in modulating the signal transduction pathways of SSTR subtypes. In the present study, we investigated human SSTR2/SSTR3 Heterodimerization, internalization, MAPK signaling, cell proliferation and apoptosis in HEK-293 cells in response to SST and specific agonists for SSTR2 and SSTR3.
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Heterodimerization of β2 adrenergic receptor and somatostatin receptor 5: Implications in modulation of signaling pathway
Journal of molecular signaling, 2011Co-Authors: Rishi K. Somvanshi, Nicole Chaudhari, Xiaofan Qiu, Ujendra KumarAbstract:Background: In the present study, we describe Heterodimerization between human-Somatostatin Receptor 5 (hSSTR5) and β 2 -Adrenergic Receptor (β 2 AR) and its impact on the receptor trafficking, coupling to adenylyl cyclase and signaling including mitogen activated protein kinases and calcineurin-NFAT pathways. Methods: We used co-immunoprecipitation, photobleaching- fluorescence resonance energy transfer and Fluorescence assisted cell sorting analysis to characterize Heterodimerization between SSTR5 and b2AR. Results: Our results indicate that hSSTR5/β 2 AR exist as preformed heterodimers in the basal condition which is enhanced upon co-activation of both receptors. In contrast, the activation of individual receptors leads to the dissociation of heterodimers. Receptor coupling to adenylyl cyclase displayed predominant effect of β 2 AR, however, somatostatin mediated inhibition of cAMP was enhanced upon blocking β 2 AR. Our results indicate hSSTR5 mediated significant activation of ERK1/2 and inhibition of phospho-p38. The phospho-NFAT level was enhanced in cotransfected cells indicating the blockade of calcineurin mediated dephosphorylation of NFAT upon receptor Heterodimerization. Conclusion: These data for the first time unveil a novel insight for the role of hSSTR5/β 2 AR in the modulation of signaling pathways which has not been addressed earlier.
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Heterooligomerization of human dopamine receptor 2 and somatostatin receptor 2 Co-immunoprecipitation and fluorescence resonance energy transfer analysis.
Cellular signalling, 2007Co-Authors: Alessandra Baragli, Haydar Alturaihi, Heather L. Watt, Ali Abdallah, Ujendra KumarAbstract:Somatostatin and dopamine receptors are well expressed and co-localized in several brain regions, suggesting the possibility of functional interactions. In the present study we used a combination of pharmacological, biochemical and photobleaching fluorescence resonance energy transfer (pbFRET) to determine the functional interactions between human somatostatin receptor 2 (hSSTR2) and human dopamine receptor 2 (hD2R) in both co-transfected CHO-K1 or HEK-293 cells as well as in cultured neuronal cells which express both the receptors endogenously. In monotransfected CHO-K1 or HEK-293 cells, D2R exists as a preformed dimer which is insensitive to agonist or antagonist treatment. In control CHO-K1 cells stably co-transfected with hD2R and hSSTR2, relatively low FRET efficiency and weak expression in co-immunoprecipitate from HEK-293 cells suggest the absence of preformed heterooligomers. However, upon treatment with selective ligands, hD2R and hSSTR2 exhibit Heterodimerization. Agonist-induced Heterodimerization was accompanied by increased affinity for dopamine and augmented hD2R signalling as well as prolonged hSSTR2 internalization. In contrast, cultured striatal neurons display constitutive Heterodimerization between D2R and SSTR2, which were agonist-independent. However, Heterodimerization in neurons was completely abolished in the presence of the D2R antagonist eticlopride. These findings suggest that hD2R and hSSTR2 operate as functional heterodimers modulated by ligands in situ, which may prove to be a useful model in designing new therapeutic drugs.