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Souza TML, Temerozo JR, Giestal-de-Araujo E, Bou-Habib DC. The effects of neurotrophins and the neuropeptides VIP and PACAP on HIV-1 infection: histories with opposite ends. Neuroimmunomodulation 2014; 21:268-82. [PMID: 24603065 DOI: 10.1159/000357434] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 11/15/2013] [Indexed: 11/19/2022] Open
Abstract
The nerve growth factor (NGF) and other neurotrophins, and the neuropeptides vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating peptide (PACAP) are largely present in human tissue and can exert modulatory activities on nervous, endocrine and immune system functions. NGF, VIP and PACAP receptors are expressed systemically in organisms, and thus these mediators exhibit pleiotropic natures. The human immunodeficiency virus type 1 (HIV-1), the causal agent of the acquired immunodeficiency syndrome (AIDS), infects immune cells, and its replication is modulated by a number of endogenous factors that interact with HIV-1-infected cells. NGF, VIP and PACAP can also affect HIV-1 virus particle production upon binding to their receptors on the membranes of infected cells, which triggers cell signaling pathways that modify the HIV-1 replicative cycle. These molecules exert opposite effects on HIV-1 replication, as NGF and other neurotrophins enhance and VIP and PACAP reduce viral production in HIV-1-infected human primary macrophages. The understanding of AIDS pathogenesis should consider the mechanisms by which the replication of HIV-1, a pathogen that causes chronic morbidity, is influenced by neurotrophins, VIP and PACAP, i.e. molecules that exert a broad spectrum of physiological activities on the neuroimmunoendocrine axis. In this review, we will present the main effects of these two groups of mediators on the HIV-1 replicative cycle, as well as the mechanisms that underlie their abilities to modulate HIV-1 production in infected immune cells, and discuss the possible repercussion of the cross talk between NGF and both neuropeptides on the pathogenesis of HIV-1 infection.
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Affiliation(s)
- Thiago Moreno L Souza
- Laboratory of Respiratory Viruses, Oswaldo Cruz Institute/Fiocruz, Rio de Janeiro, Brazil
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Couvineau A, Laburthe M. VPAC receptors: structure, molecular pharmacology and interaction with accessory proteins. Br J Pharmacol 2012; 166:42-50. [PMID: 21951273 PMCID: PMC3415636 DOI: 10.1111/j.1476-5381.2011.01676.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The vasoactive intestinal peptide (VIP) is a neuropeptide with wide distribution in both central and peripheral nervous systems, where it plays important regulatory role in many physiological processes. VIP displays a large biological functions including regulation of exocrine secretions, hormone release, fetal development, immune responses, etc. VIP appears to exert beneficial effect in neuro-degenerative and inflammatory diseases. The mechanism of action of VIP implicates two subtypes of receptors (VPAC1 and VPAC2), which are members of class B receptors belonging to the super-family of GPCR. This article reviews the current knowledge regarding the structure and molecular pharmacology of VPAC receptors. The structure-function relationship of VPAC1 receptor has been extensively studied, allowing to understand the molecular basis for receptor affinity, specificity, desensitization and coupling to adenylyl cyclase. Those studies have clearly demonstrated the crucial role of the N-terminal ectodomain (N-ted) of VPAC1 receptor in VIP recognition. By using different approaches including directed mutagenesis, photoaffinity labelling, NMR, molecular modelling and molecular dynamic simulation, it has been shown that the VIP molecule interacts with the N-ted of VPAC1 receptor, which is itself structured as a 'Sushi' domain. VPAC1 receptor also interacts with a few accessory proteins that play a role in cell signalling of receptors. Recent advances in the structural characterization of VPAC receptor and more generally of class B GPCRs will lead to the design of new molecules, which could have considerable interest for the treatment of inflammatory and neuro-degenerative diseases.
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Affiliation(s)
- Alain Couvineau
- Centre de recherche biomédicale Bichat-Beaujon, Faculté de médecine X. Bichat, Paris, France. or
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Ceraudo E, Hierso R, Tan YV, Murail S, Rouyer-Fessard C, Nicole P, Robert JC, Jamin N, Neumann JM, Robberecht P, Laburthe M, Couvineau A. Spatial proximity between the VPAC1 receptor and the amino terminus of agonist and antagonist peptides reveals distinct sites of interaction. FASEB J 2012; 26:2060-71. [PMID: 22291440 DOI: 10.1096/fj.11-196444] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Vasoactive intestinal peptide (VIP) plays a major role in pathophysiology. Our previous studies demonstrated that the VIP sequence 6-28 interacts with the N-terminal ectodomain (N-ted) of its receptor, VPAC1. Probes for VIP and receptor antagonist PG97-269 were synthesized with a photolabile residue/Bpa at various positions and used to explore spatial proximity with VPAC1. PG97-269 probes with Bpa at position 0, 6, and 24 behaved as high-affinity receptor antagonists (K(i)=12, 9, and 7 nM, respectively). Photolabeling experiments revealed that the [Bpa(0)]-VIP probe was in physical contact with VPAC1 Q(135), while [Bpa(0)]-PG97-269 was covalently bound to G(62) residue of N-ted, indicating different binding sites. In contrast, photolabeling with [Bpa(6)]- and [Bpa(24)]-PG97-269 showed that the distal domains of PG97-269 interacted with N-ted, as we previously showed for VIP. Substitution with alanine of the K(143), T(144), and T(147) residues located in the first transmembrane domain of VPAC1 induced a loss of receptor affinity (IC(50)=1035, 874, and 2070 nM, respectively), and pharmacological studies using VIP2-28 indicated that these three residues play an important role in VPAC1 interaction with the first histidine residue of VIP. These data demonstrate that VIP and PG97-269 bind to distinct domains of VPAC1.
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Affiliation(s)
- Emilie Ceraudo
- INSERM U773/CRB3, Faculté de Médecine X. Bichat, 16 rue Henri Huchard, 75018 Paris, France
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Welch MG, Anwar M, Chang CY, Gross KJ, Ruggiero DA, Gershon MD, Gershon MD. Combined administration of secretin and oxytocin inhibits chronic colitis and associated activation of forebrain neurons. Neurogastroenterol Motil 2010; 22:654-e202. [PMID: 20210978 PMCID: PMC3068601 DOI: 10.1111/j.1365-2982.2010.01477.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND The pathogenesis of inflammatory bowel disease is unknown; however, the disorder is aggravated by psychological stress and is itself psychologically stressful. Chronic intestinal inflammation, moreover, has been reported to activate forebrain neurons. We tested the hypotheses that the chronically inflamed bowel signals to the brain through the vagi and that administration of a combination of secretin (S) and oxytocin (OT) inhibits this signaling. METHODS Three daily enemas containing 2,4,6-trinitrobenzene sulfonic acid (TNBS), which were given to rats produced chronic colitis and ongoing activation of Fos in brain neurons. KEY RESULTS Fos was induced in neurons in the paraventricular nucleus of the hypothalamus, basolateral amygdala, central amygdala, and piriform cortex. Subdiaphragmatic vagotomy failed to inhibit this activation of Fos, suggesting that colitis activates forebrain neurons independently of the vagi. When administered intravenously, but not when given intracerebroventricularly, in doses that were individually ineffective, combined S/OT prevented colitis-associated activation of central neurons. Strikingly, S/OT decreased inflammatory infiltrates into the colon and colonic expression of tumor necrosis factor-alpha and interferon-gamma. CONCLUSIONS & INFERENCES These observations suggest that chronic colonic inflammation is ameliorated by the systemic administration of S/OT, which probably explains the parallel ability of systemic S/OT to inhibit the colitis-associated activation of forebrain neurons. It is possible that S and OT, which are endogenous to the colon, might normally combine to restrict the severity of colonic inflammatory responses and that advantage might be taken of this system to develop novel means of treating inflammation-associated intestinal disorders.
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Affiliation(s)
- Martha G. Welch
- Dept. of Psychiatry, Columbia Univ. College of P & S, 1051 Riverside Drive Unit 40, NY, NY, 10032,Dept. of Pathology & Cell Biology, Columbia U. College of P & S, 630 West 168th Street, NY, NY, 10032
| | - Muhammad Anwar
- Dept. of Psychiatry, Columbia Univ. College of P & S, 1051 Riverside Drive Unit 40, NY, NY, 10032
| | - Christine Y. Chang
- Dept. of Psychiatry, Columbia Univ. College of P & S, 1051 Riverside Drive Unit 40, NY, NY, 10032,Dept. of Pathology & Cell Biology, Columbia U. College of P & S, 630 West 168th Street, NY, NY, 10032
| | - Kara J. Gross
- Dept. of Pathology & Cell Biology, Columbia U. College of P & S, 630 West 168th Street, NY, NY, 10032
| | - David A. Ruggiero
- Dept. of Psychiatry, Columbia Univ. College of P & S, 1051 Riverside Drive Unit 40, NY, NY, 10032,Dept. of Pathology & Cell Biology, Columbia U. College of P & S, 630 West 168th Street, NY, NY, 10032
| | - Michael D. Gershon
- Dept. of Pathology & Cell Biology, Columbia U. College of P & S, 630 West 168th Street, NY, NY, 10032
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Pioszak AA, Xu HE. Molecular recognition of parathyroid hormone by its G protein-coupled receptor. Proc Natl Acad Sci U S A 2008; 105:5034-9. [PMID: 18375760 PMCID: PMC2278174 DOI: 10.1073/pnas.0801027105] [Citation(s) in RCA: 194] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Indexed: 11/18/2022] Open
Abstract
Parathyroid hormone (PTH) is central to calcium homeostasis and bone maintenance in vertebrates, and as such it has been used for treating osteoporosis. It acts primarily by binding to its receptor, PTH1R, a member of the class B G protein-coupled receptor (GPCR) family that also includes receptors for glucagon, calcitonin, and other therapeutically important peptide hormones. Despite considerable interest and much research, determining the structure of the receptor-hormone complex has been hindered by difficulties in purifying the receptor and obtaining diffraction-quality crystals. Here, we present a method for expression and purification of the extracellular domain (ECD) of human PTH1R engineered as a maltose-binding protein (MBP) fusion that readily crystallizes. The 1.95-A structure of PTH bound to the MBP-PTH1R-ECD fusion reveals that PTH docks as an amphipathic helix into a central hydrophobic groove formed by a three-layer alpha-beta-betaalpha fold of the PTH1R ECD, resembling a hot dog in a bun. Conservation in the ECD scaffold and the helical structure of peptide hormones emphasizes this hot dog model as a general mechanism of hormone recognition common to class B GPCRs. Our findings reveal critical insights into PTH actions and provide a rational template for drug design that targets this hormone signaling pathway.
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MESH Headings
- Amino Acid Sequence
- Animals
- Cattle
- Conserved Sequence
- Crystallography, X-Ray
- Gene Expression
- Humans
- Models, Molecular
- Molecular Sequence Data
- Parathyroid Hormone/chemistry
- Parathyroid Hormone/metabolism
- Protein Binding
- Protein Structure, Quaternary
- Receptor, Parathyroid Hormone, Type 1/chemistry
- Receptor, Parathyroid Hormone, Type 1/genetics
- Receptor, Parathyroid Hormone, Type 1/isolation & purification
- Receptor, Parathyroid Hormone, Type 1/metabolism
- Sensitivity and Specificity
- Sequence Alignment
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Affiliation(s)
- Augen A. Pioszak
- Laboratory of Structural Sciences, Van Andel Research Institute, 333 Bostwick Avenue, N.E., Grand Rapids, MI 49503
| | - H. Eric Xu
- Laboratory of Structural Sciences, Van Andel Research Institute, 333 Bostwick Avenue, N.E., Grand Rapids, MI 49503
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Couvineau A, Rouyer-Fessard C, Laburthe M. Presence of a N-terminal signal peptide in class II G protein-coupled receptors: crucial role for expression of the human VPAC1 receptor. REGULATORY PEPTIDES 2004; 123:181-5. [PMID: 15518910 DOI: 10.1016/j.regpep.2004.06.025] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The hVPAC1 receptor for vasoactive intestinal peptide (VIP) and pituitary adenylyl cyclase activating peptide (PACAP) has an N-terminal signal peptide like all other class II G protein-coupled receptors (GPCRs). We determined the role of the signal peptide in expression of human VPAC1 receptor in transfected CHO cells. Three constructs were transfected: Flag30-hVPAC1, a receptor containing an inserted FLAG sequence between Ala30 and Ala31 and fused in the C-terminal position to GFP; Flag30-[delta1-30]-hVPAC1, the same construct as Flag30-hVPAC1 but lacking the 1-30 putative signal peptide (SP) sequence; Flag0-hVPAC1, a receptor containing an N-terminal FLAG sequence and fused in the C-terminal position to GFP. For each construct, we determined 125I-VIP binding, VIP-induced cAMP production, GFP fluorescence and indirect immunofluorescence on nonpermeabilized cells incubated with mouse monoclonal anti-Flag antibodies. The data were consistent with a crucial role of the signal peptide for expression of functional VPAC1 receptors at the cell surface and suggested that the signal peptide is cleaved during the translocation of the receptor to the plasma membrane, probably in the endoplasmic reticulum.
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Affiliation(s)
- Alain Couvineau
- INSERM U410, Neuroendocrinologie et Biologie Cellulaire Digestives, Institut National de la Santé et de la Recherche Médicale, Faculté de Médecine Xavier Bichat, Paris F-75018, France.
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Tan YV, Couvineau A, Laburthe M. Diffuse pharmacophoric domains of vasoactive intestinal peptide (VIP) and further insights into the interaction of VIP with the N-terminal ectodomain of human VPAC1 receptor by photoaffinity labeling with [Bpa6]-VIP. J Biol Chem 2004; 279:38889-94. [PMID: 15247290 DOI: 10.1074/jbc.m404460200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The widespread 28-amino acid neuropeptide vasoactive intestinal peptide (VIP) exerts its many biological effects through interaction with serpentine class II G protein-coupled receptors named VPAC receptors. We previously provided evidence for a physical contact between the side chain at position 22 of VIP and the N-terminal ectodomain of the hVPAC1 receptor (Tan, Y. V., Couvineau, A., Van Rampelbergh, J., and Laburthe, M. (2003) J. Biol. Chem. 278, 36531-36536). We explored here the contact site between hVPAC1 receptor and the side chain at position 6 of VIP by photoaffinity labeling. The photoreactive para-benzoyl-l-Phe (Bpa) was substituted for Phe(6) in VIP resulting in [Bpa(6)]-VIP, which was shown to be a hVPAC1 receptor agonist in Chinese hamster ovary cells stably expressing the recombinant receptor. After obtaining the covalent (125)I-[Bpa(6)-VIP].hVPAC1 receptor complex, it was sequentially cleaved by cyanogen bromide, peptide N-glycosidase F, endopeptidase Glu-C, and trypsin, and the cleavage products were analyzed by electrophoresis. The data demonstrated that (125)I-[Bpa(6)-VIP] were covalently attached to the short 104-108 fragment within the N-terminal ectodomain of the receptor. The data were confirmed by creation of a receptor mutant with new CNBr cleavage site. In a three-dimensional model of the receptor N-terminal ectodomain, this fragment was located on one edge of the putative VIP-binding groove and was adjacent to the fragment covalently attached to the side chain at position 22 of VIP. Altogether these data showed that the central part of VIP, at least between Phe(6) and Tyr(22), interacts with the N-terminal ectodomain of the hVPAC1 receptor.
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Affiliation(s)
- Yossan-Var Tan
- INSERM U410, Neuroendocrinologie et Biologie Cellulaire Digestives, Institut National de la Santé et de la Recherche Médicale, Faculté de Médecine Xavier Bichat, Paris F-75018, France
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Marie JC, Rouyer-Fessard C, Couvineau A, Nicole P, Devaud H, El Benna J, Laburthe M. Serine 447 in the carboxyl tail of human VPAC1 receptor is crucial for agonist-induced desensitization but not internalization of the receptor. Mol Pharmacol 2003; 64:1565-74. [PMID: 14645688 DOI: 10.1124/mol.64.6.1565] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The VPAC1 receptor for vasoactive intestinal peptide (VIP) belongs to the class II family of G protein-coupled receptors and is coupled to Gs protein/adenylyl cyclase. We assessed whether 10 different Ser/Thr residues in human VPAC1 receptor intracellular domains play a role in the process of VIP-induced desensitization/internalization by performing a site-directed mutagenesis study. The Ser/Thr residues mutated to Ala include potential G protein-coupled receptor kinase, protein kinase A and protein kinase C targets that are of particular interest for VPAC1 receptor desensitization. The data show that when Chinese hamster ovary cells expressing wild-type receptors were pretreated for 5 min with VIP (50 nM), receptor desensitization occurred with a 10-fold right shift of the ED50 for adenylyl cyclase activation. When the construct with the widest span of mutations was studied, there was no longer any short-term desensitization. By using constructs with fewer and fewer mutations, we identified Ser447 in the C-terminal tail to be crucial for rapid desensitization. We also showed that Ser447 plays an essential role for VIP-induced VPAC1 phosphorylation in Chinese hamster ovary cells. Furthermore, we demonstrated that none of the mutated Ser/Thr residues was involved in down-regulation after a 12-h treatment of cells with 50 nM VIP. Neither were they involved in VIP and VIP-induced receptor internalization as shown using a novel fluorescein-tagged VIP and VPAC1 receptor bearing a Flag epitope in the N-terminal domain and a green fluorescent protein at the C terminus. We conclude that Ser447, a likely G protein-coupled receptor kinase target, is crucial for VIP-induced phosphorylation and rapid desensitization of VPAC1 receptor.
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Affiliation(s)
- Jean-Claude Marie
- INSERM U410, Faculté de Médecine Xavier Bichat, 75018 Paris, France.
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Tan YV, Couvineau A, Van Rampelbergh J, Laburthe M. Photoaffinity labeling demonstrates physical contact between vasoactive intestinal peptide and the N-terminal ectodomain of the human VPAC1 receptor. J Biol Chem 2003; 278:36531-6. [PMID: 12807902 DOI: 10.1074/jbc.m304770200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Vasoactive intestinal peptide (VIP) is a prominent neuropeptide whose actions are mediated by VPAC receptors belonging to class II G protein-coupled receptors. To identify contact sites between VIP and its VPAC1 receptor, an analog of VIP substituted with a photoreactive para-benzoyl-l-Phe (Bpa) at position 22 has been synthesized and evaluated in Chinese hamster ovary cells stably expressing the recombinant human receptor. Bpa22-VIP and native VIP are equipotent in stimulating adenylyl cyclase activity in cell membranes. Cyanogen bromide cleavage of the covalent 125I-[Bpa22-VIP]-hVPAC1R complex yielded a single labeled fragment of 30 kDa that shifted to 11 after deglycosylation, most consistent with the 67-137 fragment of the receptor N-terminal ectodomain. Further cleavage of this fragment with V8 endoproteinase and creation of receptor mutants with new CNBr cleavage sites (XàMet), demonstrated that 125I-[Bpa22-VIP] was covalently attached to the short receptor 109-120 fragment (GWTHLEPGPYPI). In a three-dimensional model of the receptor N-terminal ectodomain, this fragment is located on one edge of the putative VIP binding groove and encompasses several amino acids previously shown to be crucial for VIP binding (reviewed in Laburthe, M., Couvineau, A., and Marie, J. C. (2002) Receptors Channels 8, 137-153). Our data provide the first direct evidence for a physical contact between VIP and the N-terminal ectodomain of the hVPAC1 receptor.
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Affiliation(s)
- Yossan-Var Tan
- INSERM U410, Neuroendocrinologie et Biologie Cellulaire Digestives, Institut National de la Santé et de la Recherche Médicale, Faculté de Médecine Xavier Bichat, Paris F-75018, France
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Couvineau A, Lacapere JJ, Tan YV, Rouyer-Fessard C, Nicole P, Laburthe M. Identification of cytoplasmic domains of hVPAC1 receptor required for activation of adenylyl cyclase. Crucial role of two charged amino acids strictly conserved in class II G protein-coupled receptors. J Biol Chem 2003; 278:24759-66. [PMID: 12690118 DOI: 10.1074/jbc.m301916200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The VPAC1 receptor mediates the action of two neuropeptides, vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating peptide. It is a class II G protein-coupled receptor-activating adenylyl cyclase (AC). The role of the N-terminal extracellular domain of hVPAC1 receptor for VIP binding is now established (Laburthe, M., Couvineau, A. and Marie, J. C. (2002) Recept. Channels 8, 137-153), but nothing is known regarding the cytoplasmic domains responsible for AC activation. Here, we constructed a large series of mutants by substituting amino acids with alanine in the intracellular loops (IL) 1, 2, and 3 and proximal C-terminal tail of the receptor. The mutation of 40 amino acids followed by expression of mutants in chinese hamster ovary cells showed the following. (i) Mutations IL1 result in the absence of expression of mutants, suggesting a role of this loop in receptor folding. (ii) All residues of IL2 can be mutated without alteration of receptor expression and AC response to VIP. (iii) Mutation of residues IL3 points to the specific role of lysine 322 in the efficacy of the stimulation of AC activity by VIP. This efficacy is reduced by 50% in the K322A mutant. (iv) The proximal C-terminal tail is equipped with another important amino acid since mutation of glutamic acid 394 reduces AC response by 50%. The double mutant K322A/E394A exhibits a drastic reduction of >85% in the efficacy of VIP in stimulating AC activity in membranes and cAMP response in intact cells without alteration of receptor expression or affinity for VIP. These data highlight the role of charged residues in IL3 and the proximal C-terminal tail of hVPAC1 receptor for agonist-induced AC activation. Because these charged residues are absolutely conserved in class II receptors for peptides, which are all mediating AC activation, they may play a general role in coupling of class II receptors with the Gs protein.
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Affiliation(s)
- Alain Couvineau
- INSERM U410 Neuroendocrinologie et Biologie Cellulaire Digestives, Institut National de la Santé et de la Recherche Médicale, Faculté de Médecine Xavier Bichat, F-75018 Paris, France.
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