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O’Flynn NJ, Patel A, Kadlec J, Jones I. Improving promiscuous mammalian cell entry by the baculovirus Autographa californica multiple nuclear polyhedrosis virus. Biosci Rep 2012; 33:23-36. [PMID: 23035899 PMCID: PMC3522474 DOI: 10.1042/bsr20120093] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 09/25/2012] [Accepted: 10/02/2012] [Indexed: 02/08/2023] Open
Abstract
The insect baculovirus AcMNPV (Autographa californica multiple nuclear polyhedrosis virus) enters many mammalian cell lines, prompting its application as a general eukaryotic gene delivery agent, but the basis of entry is poorly understood. For adherent mammalian cells, we show that entry is favoured by low pH and by increasing the available cell-surface area through a transient release from the substratum. Low pH also stimulated baculovirus entry into mammalian cells grown in suspension which, optimally, could reach 90% of the transduced population. The basic loop, residues 268-281, of the viral surface glycoprotein gp64 was required for entry and a tetra mutant with increasing basicity increased entry into a range of mammalian cells. The same mutant failed to plaque in Sf9 cells, instead showing individual cell entry and minimal cell-to-cell spread, consistent with an altered fusion phenotype. Viruses grown in different insect cells showed different mammalian cell entry efficiencies, suggesting that additional factors also govern entry.
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Key Words
- baculovirus
- fusion
- gene transduction
- gp64
- mammalian cell
- virus entry
- acmnpv, autographa californica multiple nuclear polyhedrosis virus
- atcp, amorphous tricalcium phosphate
- cf, carboxyfluorescein
- cho, chinese-hamster ovary
- dmem, dulbecco’s modified eagle’s medium
- egfp, enhanced green fluorescent protein
- fcs, fetal calf serum
- hek-293t, hek-293 cells expressing the large t-antigen of sv40 (simian virus 40)
- ie1, immediate early 1
- moi, multiplicity of infection
- mab, monoclonal antibody
- npv, nucleopolyhedrosis virus
- pc, phosphatidylcholine
- pbs-t, pbs containing 0.1% tween 20
- pe, phosphatidylethanolamine
- pi, phosphatidylinositol
- popc, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine
- popg, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol
- qpcr, quantitative pcr
- rmsd, root mean square deviation
- vsv g, vesicular-stomatitis virus glycoprotein g
- wt, wild-type
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Affiliation(s)
- Neil M. J. O’Flynn
- *School of Biological Sciences, University of Reading, Reading RG6 6AJ, U.K
| | - Avnish Patel
- *School of Biological Sciences, University of Reading, Reading RG6 6AJ, U.K
| | - Jan Kadlec
- †European Molecular Biology Laboratory, BP 181, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9, France
| | - Ian M. Jones
- *School of Biological Sciences, University of Reading, Reading RG6 6AJ, U.K
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Watschinger K, Fuchs J, Yarov-Yarovoy V, Keller M, Golderer G, Hermetter A, Werner-Felmayer G, Hulo N, Werner E. Catalytic residues and a predicted structure of tetrahydrobiopterin-dependent alkylglycerol mono-oxygenase. Biochem J 2012; 443:279-86. [PMID: 22220568 PMCID: PMC3304488 DOI: 10.1042/bj20111509] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Revised: 12/22/2011] [Accepted: 01/06/2012] [Indexed: 11/17/2022]
Abstract
Alkylglycerol mono-oxygenase (EC 1.14.16.5) forms a third, distinct, class among tetrahydrobiopterin-dependent enzymes in addition to aromatic amino acid hydroxylases and nitric oxide synthases. Its protein sequence contains the fatty acid hydroxylase motif, a signature indicative of a di-iron centre, which contains eight conserved histidine residues. Membrane enzymes containing this motif, including alkylglycerol mono-oxygenase, are especially labile and so far have not been purified to homogeneity in active form. To obtain a first insight into structure-function relationships of this enzyme, we performed site-directed mutagenesis of 26 selected amino acid residues and expressed wild-type and mutant proteins containing a C-terminal Myc tag together with fatty aldehyde dehydrogenase in Chinese-hamster ovary cells. Among all of the acidic residues within the eight-histidine motif, only mutation of Glu137 to alanine led to an 18-fold increase in the Michaelis-Menten constant for tetrahydrobiopterin, suggesting a role in tetrahydrobiopterin interaction. A ninth additional histidine residue essential for activity was also identified. Nine membrane domains were predicted by four programs: ESKW, TMHMM, MEMSAT and Phobius. Prediction of a part of the structure using the Rosetta membrane ab initio method led to a plausible suggestion for a structure of the catalytic site of alkylglycerol mono-oxygenase.
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Affiliation(s)
- Katrin Watschinger
- *Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Fritz-Pregl-Strasse 3/VI, A-6020 Innsbruck, Austria
| | - Julian E. Fuchs
- †Institute of General, Inorganic and Theoretical Chemistry, Innrain 52a, Leopold Franzens University Innsbruck, A-6020 Innsbruck, Austria
| | - Vladimir Yarov-Yarovoy
- ‡Department of Physiology and Membrane Biology, School of Medicine, Room 4131, Tupper Hall, University of California, Davis, One Shields Avenue, Davis, CA 95616, U.S.A
| | - Markus A. Keller
- *Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Fritz-Pregl-Strasse 3/VI, A-6020 Innsbruck, Austria
| | - Georg Golderer
- *Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Fritz-Pregl-Strasse 3/VI, A-6020 Innsbruck, Austria
| | - Albin Hermetter
- §Institute of Biochemistry, Graz University of Technology, Petersgasse 12/2, A-8010 Graz, Austria
| | - Gabriele Werner-Felmayer
- *Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Fritz-Pregl-Strasse 3/VI, A-6020 Innsbruck, Austria
| | - Nicolas Hulo
- ∥Swiss Institute for Bioinformatics, Centre Medical Universitaire, 1 rue Michel Servet, CH-1211 Geneva, Switzerland
| | - Ernst R. Werner
- *Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Fritz-Pregl-Strasse 3/VI, A-6020 Innsbruck, Austria
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Brown A, Bill J, Tully T, Radhamohan A, Dowd C. Overloading ion-exchange membranes as a purification step for monoclonal antibodies. Biotechnol Appl Biochem 2010; 56:59-70. [PMID: 20497123 PMCID: PMC2891000 DOI: 10.1042/ba20090369] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 05/06/2010] [Accepted: 05/19/2010] [Indexed: 11/30/2022]
Abstract
The present study examined the overloading of ion-exchange membrane adsorbers, a form of frontal chromatography, as the final purification step in the production of mAbs (monoclonal antibodies) produced from CHO (Chinese-hamster ovary) cells. Preferential binding of impurities over antibody product was exploited using commercially available cation- and anion-exchange membranes. Three different antibody feedstreams previously purified over Protein A and ion-exchange column chromatography were tested. Feedstream conductivity and pH were adjusted to induce product and impurity adsorption. Membranes were then overloaded in a normal flow mode, resulting in retention of impurities and breakthrough of purified antibody. Although some amount of the product also binds to the membranes (usually < or =30 g mAb/l membrane), yields of > or =99% were achieved by marginalizing the losses, typically by loading more than 3 kg mAb/l membrane. Analyses of the purified pools show consistent removal of impurities despite strong mAb-ligand interactions and high membrane loadings. The clearance of host cell proteins was affected by pH and conductivity, but was unaffected by flow rate, membrane properties or scale. The importance of the present study lies in our demonstration of an alternative use of ion-exchange membranes for fast, effective and high yielding purification of mAbs.
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Affiliation(s)
- Arick Brown
- Process Technical Development, Genentech, 1 DNA Way, South San Francisco, CA 94080, USA.
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Riedle S, Kiefel H, Gast D, Bondong S, Wolterink S, Gutwein P, Altevogt P. Nuclear translocation and signalling of L1-CAM in human carcinoma cells requires ADAM10 and presenilin/gamma-secretase activity. Biochem J 2009; 420:391-402. [PMID: 19260824 PMCID: PMC2782312 DOI: 10.1042/bj20081625] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 02/19/2009] [Accepted: 03/05/2009] [Indexed: 12/31/2022]
Abstract
L1-CAM (L1 cell-adhesion molecule), or more simply L1, plays an important role in the progression of human carcinoma. Overexpression promotes tumour-cell invasion and motility, growth in nude mice and tumour metastasis. It is feasible that L1-dependent signalling contributes to these effects. However, little is known about its mechanism in tumour cells. We reported previously that L1 is cleaved by ADAM (a disintegrin and metalloprotease) and that the cytoplasmic part is essential for L1 function. Here we analysed more closely the role of proteolytic cleavage in L1-mediated nuclear signalling. Using OVMz carcinoma cells and L1-transfected cells as a model, we found that ADAM10-mediated cleavage of L1 proceeds in lipid raft and non-raft domains. The cleavage product, L1-32, is further processed by PS (presenilin)/gamma-secretase to release L1-ICD, an L1 intracellular domain of 28 kDa. Overexpression of dominant-negative PS1 or use of a specific gamma-secretase inhibitor leads to an accumulation of L1-32. Fluorescence and biochemical analysis revealed a nuclear localization for L1-ICD. Moreover, inhibition of ADAM10 and/or gamma-secretase blocks nuclear translocation of L1-ICD and L1-dependent gene regulation. Overexpression of recombinant L1-ICD mediates gene regulation in a similar manner to full-length L1. Our results establish for the first time that regulated proteolytic processing by ADAM10 and PS/gamma-secretase is essential for the nuclear signalling of L1 in human carcinoma cell lines.
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Key Words
- a disintegrin and metalloprotease 10 (adam10)
- l1 cell-adhesion molecule (l1-cam)
- nuclear translocation
- presenilin (ps)/γ-secretase activity
- raft
- signalling
- adam, a disintegrin and metalloprotease
- app, amyloid precursor protein
- cho, chinese-hamster ovary
- crabpii, cellular retinoic acid-binding protein ii
- ctf, c-terminal fragment
- dapt, n-[n-(3,5-difluorophenacetyl)-l-alanyl]-(s)-phenylglycine t-butyl ester (also known as presenilin inhibitor ix)
- drm, detergent-resistant membrane
- ecl®, enhanced chemiluminescence
- erk, extracellular-signal-regulated kinase
- fcs, fetal-calf serum
- fniii, fibronectin iii
- hek-293, human embryonic kidney-293
- hl1, human l1
- hrp, horseradish peroxidase
- icd, intracellular domain
- lamp-1, lysosomal-associated membrane protein 1
- l1, l1 cell-adhesion molecule
- l1cyt, the cytoplasmic part of l1
- mab, monoclonal antibody
- mdk, midkine or neurite growth-promoting factor 2
- mt1-mmp, membrane type-1 matrix metalloproteinase
- pab, polyclonal antibody
- ps(1), presenilin(-1)
- qrt-pcr, quantitative real-time pcr
- rip, regulated intramembrane proteolysis
- sirna, small interfering rna
- tace, tumour-necrosis factor-α converting enzyme
- tapi-0, n-(r)-[2-(hydroxyaminocarbonyl)methyl]-4-methylpentanoyl-l-naphthylalanyl-l-alanine amide
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Affiliation(s)
- Svenja Riedle
- *Translational Immunology, D015, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Federal Republic of Germany
| | - Helena Kiefel
- *Translational Immunology, D015, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Federal Republic of Germany
| | - Daniela Gast
- *Translational Immunology, D015, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Federal Republic of Germany
| | - Sandra Bondong
- *Translational Immunology, D015, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Federal Republic of Germany
| | - Silke Wolterink
- *Translational Immunology, D015, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Federal Republic of Germany
| | - Paul Gutwein
- †Center for Pharmacology, University of Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Federal Republic of Germany
| | - Peter Altevogt
- *Translational Immunology, D015, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120 Heidelberg, Federal Republic of Germany
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Mozo J, Ferry G, Studeny A, Pecqueur C, Rodriguez M, Boutin J, Bouillaud F. Expression of UCP3 in CHO cells does not cause uncoupling, but controls mitochondrial activity in the presence of glucose. Biochem J 2006; 393:431-9. [PMID: 16178820 PMCID: PMC1383702 DOI: 10.1042/bj20050494] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2005] [Revised: 09/19/2005] [Accepted: 09/23/2005] [Indexed: 12/16/2022]
Abstract
The proton-transport activity of UCP1 (uncoupling protein 1) triggers mitochondrial uncoupling and thermogenesis. The exact role of its close homologues, UCP2 and UCP3, is unclear. Mounting evidence associates them with the control of mitochondrial superoxide production. Using CHO (Chinese-hamster ovary) cells stably expressing UCP3 or UCP1, we found no evidence for respiration uncoupling. The explanation lies in the absence of an appropriate activator of UCP protonophoric function. Accordingly, the addition of retinoic acid uncouples the respiration of the UCP1-expressing clone, but not that of the UCP3-expressing ones. In a glucose-containing medium, the extent of the hyperpolarization of mitochondria by oligomycin was close to 22 mV in the five UCP3-expressing clones, contrasting with the variable values observed with the 15 controls. Our observations suggest that, when glycolysis and mitochondria generate ATP, and in the absence of appropriate activators of proton transport, UCPs do not transport protons (uncoupling), but rather other ions of physiological relevance that control mitochondrial activity. A model is proposed using the known passive transport of pyruvate by UCP1.
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Affiliation(s)
- Julien Mozo
- *BIOTRAM (Transporteurs Mitochondriaux et Métabolisme) CNRS UPR9078, Faculté de Médecine René Descartes Paris 5, site Necker, 156 rue de Vaugirard 75730 Paris, France
| | - Gilles Ferry
- †Institut de Recherches Servier, 125 chemin de Ronde, 78290 Croissy-sur-Seine, France
| | - Aurélie Studeny
- †Institut de Recherches Servier, 125 chemin de Ronde, 78290 Croissy-sur-Seine, France
| | - Claire Pecqueur
- *BIOTRAM (Transporteurs Mitochondriaux et Métabolisme) CNRS UPR9078, Faculté de Médecine René Descartes Paris 5, site Necker, 156 rue de Vaugirard 75730 Paris, France
| | - Marianne Rodriguez
- †Institut de Recherches Servier, 125 chemin de Ronde, 78290 Croissy-sur-Seine, France
| | - Jean A. Boutin
- †Institut de Recherches Servier, 125 chemin de Ronde, 78290 Croissy-sur-Seine, France
| | - Frédéric Bouillaud
- *BIOTRAM (Transporteurs Mitochondriaux et Métabolisme) CNRS UPR9078, Faculté de Médecine René Descartes Paris 5, site Necker, 156 rue de Vaugirard 75730 Paris, France
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Niv-Spector L, Gonen-Berger D, Gourdou I, Biener E, Gussakovsky E, Benomar Y, Ramanujan K, Taouis M, Herman B, Callebaut I, Djiane J, Gertler A. Identification of the hydrophobic strand in the A-B loop of leptin as major binding site III: implications for large-scale preparation of potent recombinant human and ovine leptin antagonists. Biochem J 2005; 391:221-30. [PMID: 15952938 PMCID: PMC1276919 DOI: 10.1042/bj20050457] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2005] [Revised: 05/16/2005] [Accepted: 06/14/2005] [Indexed: 01/29/2023]
Abstract
Interaction of leptin with its receptors resembles that of interleukin-6 and granulocyte colony-stimulating factor, which interact with their receptors through binding sites I-III. Site III plays a pivotal role in receptors' dimerization or tetramerization and subsequent activation. Leptin's site III also mediates the formation of an active multimeric complex through its interaction with the IGD (immunoglobulin-like domain) of LEPRs (leptin receptors). Using a sensitive hydrophobic cluster analysis of leptin's and LEPR's sequences, we identified hydrophobic stretches in leptin's A-B loop (amino acids 39-42) and in the N-terminal end of LEPR's IGD (amino acids 325-328) that are predicted to participate in site III and to interact with each other in a beta-sheet-like configuration. To verify this hypothesis, we prepared and purified to homogeneity (as verified by SDS/PAGE, gel filtration and reverse-phase chromatography) several alanine muteins of amino acids 39-42 in human and ovine leptins. CD analyses revealed that those mutations hardly affect the secondary structure. All muteins acted as true antagonists, i.e. they bound LEPR with an affinity similar to the wild-type hormone, had no agonistic activity and specifically inhibited leptin action in several leptin-responsive in vitro bioassays. Alanine mutagenesis of LEPR's IGD (amino acids 325-328) drastically reduced its biological but not binding activity, indicating the importance of this region for interaction with leptin's site III. FRET (fluorescence resonance energy transfer) microscopy experiments have documented that the transient FRET signalling occurring upon exposure to leptin results not from binding of the ligand, but from ligand-induced oligomerization of LEPRs mediated by leptin's site III.
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Key Words
- a–b loop of leptin
- antagonists
- fluorescence resonance energy transfer (fret)
- hydrophobic strand
- immunoglobulin-like domain (igd)
- site-directed mutagenesis
- apb, acceptor photobleaching
- cfp, cyan fluorescent protein
- ch, chicken
- cho, chinese-hamster ovary
- crh, cytokine receptor homology domain
- erk, extracellular-signal-regulated kinase
- g-csf, granulocyte colony-stimulating factor
- h, human
- hca, hydrophobic cluster analysis
- hek-293t cells, human embryonic kidney 293t cells
- ibs, inclusion bodies
- il-6, interleukin-6
- igd, immunoglobulin-like domain
- lbd, leptin-binding domain
- lepr, leptin receptor
- m, mouse
- mapk, mitogen-activated protein kinase
- mtt, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2h-tetrazolium bromide
- spr, surface plasmon resonance, stat3, signal transducer and activator of transcription 3
- tfa, trifluoroacetic acid
- v, viral
- wt, wild-type
- yfp, yellow fluorescent protein
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Affiliation(s)
- Leonora Niv-Spector
- *Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University, Rehovot 76100, Israel
| | - Dana Gonen-Berger
- *Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University, Rehovot 76100, Israel
| | - Isabelle Gourdou
- †Institut National de la Recherche Agronomique, Neuroendocrinologie Moleculaire de la Prise Alimentaire, 78352 Jouy-en-Josas Cedex, France
| | - Eva Biener
- *Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University, Rehovot 76100, Israel
| | - Eugene E. Gussakovsky
- ‡Department of Life Sciences, Bar Ilan University, Ramat Gan 52900, Israel
- §Institute of Horticulture, The Volcani Center, Agricultural Research Organization, Bet Dagan 50250, Israel
| | - Yackir Benomar
- ∥Laboratoire d'Endocrinologie, University of Paris XI, Orsay 91405, France
| | - Krishnan V. Ramanujan
- ¶Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, U.S.A
| | - Mohammed Taouis
- ∥Laboratoire d'Endocrinologie, University of Paris XI, Orsay 91405, France
| | - Brian Herman
- ¶Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229, U.S.A
| | - Isabelle Callebaut
- **Institut de Mineralogie et de Physique des Milieux Condenses, CNRS UMR7590, Universities Paris 6 & Paris 7, Paris Cedex 05, France
| | - Jean Djiane
- †Institut National de la Recherche Agronomique, Neuroendocrinologie Moleculaire de la Prise Alimentaire, 78352 Jouy-en-Josas Cedex, France
| | - Arieh Gertler
- *Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University, Rehovot 76100, Israel
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Steiner D, Avidor-Reiss T, Schallmach E, Butovsky E, Lev N, Vogel Z. Regulation of adenylate cyclase type VIII splice variants by acute and chronic Gi/o-coupled receptor activation. Biochem J 2005; 386:341-8. [PMID: 15537392 PMCID: PMC1134799 DOI: 10.1042/bj20041670] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2004] [Revised: 11/03/2004] [Accepted: 11/10/2004] [Indexed: 11/17/2022]
Abstract
We previously reported that acute agonist activation of G(i/o)-coupled receptors inhibits adenylate cyclase (AC) type VIII activity, whereas agonist withdrawal following chronic activation of these receptors induces AC-VIII superactivation. Three splice variants of AC-VIII have been identified, which are called AC-VIII-A, -B and -C (with AC-VIII-B missing the glycosylation domain and AC-VIII-C lacking most of the C1b area). We report here that AC-VIII-A and -B, but not -C, are inhibited by acute mu-opioid and dopaminergic type D2 receptor activation, indicating that the C1b area of AC-VIII has an important role in AC inhibition by G(i/o)-coupled receptor activation. On the other hand the glycosylation sites in AC-VIII did not play a role in AC-VIII regulation. Although AC-VIII-A and -C differed in their capacity to be inhibited by acute agonist exposure, agonist withdrawal after prolonged treatment led to a similar superactivation of all three splice variants, with no significant change in AC-VIII expression. AC-VIII superactivation was not affected by pre-incubation with a cell permeable cAMP analogue, indicating that the superactivation does not depend on the agonist-induced reduction in cAMP levels. The superactivated AC-VIII-A, -B and -C were similarly re-inhibited by re-application of agonist (morphine or quinpirole), returning the activity to control levels. These results demonstrate marked differences in the agonist inhibition of the AC-VIII splice variants before, but not after, superactivation.
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Key Words
- adenylate cyclase type viii
- camp
- dopamine receptor
- g-protein-coupled receptor
- opiate receptor
- superactivation
- ac, adenylate cyclase
- cho, chinese-hamster ovary
- 8-cpt-camp, 8-(4-chlorophenylthio)-3′,5′-camp
- dmem, dulbecco's modified eagle's medium
- d2 receptor, dopaminergic type 2 receptor
- d2l receptor, long form of the d2 receptor
- fs, forskolin
- ibmx, isobutylmethylxanthine
- ptx, pertussis toxin
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Affiliation(s)
- Debora Steiner
- Department of Neurobiology, The Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Tomer Avidor-Reiss
- Department of Neurobiology, The Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Ester Schallmach
- Department of Neurobiology, The Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Elena Butovsky
- Department of Neurobiology, The Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Nirit Lev
- Department of Neurobiology, The Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Zvi Vogel
- Department of Neurobiology, The Weizmann Institute of Science, 76100 Rehovot, Israel
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Triantafilou M, Brandenburg K, Kusumoto S, Fukase K, Mackie A, Seydel U, Triantafilou K. Combinational clustering of receptors following stimulation by bacterial products determines lipopolysaccharide responses. Biochem J 2004; 381:527-36. [PMID: 15040785 PMCID: PMC1133861 DOI: 10.1042/bj20040172] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2004] [Revised: 03/15/2004] [Accepted: 03/24/2004] [Indexed: 01/12/2023]
Abstract
The innate immune system has the capacity to recognize a wide range of pathogens based on conserved PAMPs (pathogen-associated molecular patterns). In the case of bacterial LPS (lipopolysaccharide) recognition, the best studied PAMP, it has been shown that the innate immune system employs at least three cell-surface receptors: CD14, TLR4 (Toll-like receptor 4) and MD-2 protein. CD14 binds LPS from Enterobacteriaceae and then transfers it to MD-2, leading to TLR4 aggregation and signal transduction. LPS analogues such as lipid IVa seem to act as LPS antagonists in human cells, but exhibit LPS mimetic activity in mouse cells. Although TLR4 has been shown to be involved in this species-specific discrimination, the mechanism by which this is achieved has not been elucidated. The questions that remain are how the innate immune system can discriminate between LPS from different bacteria as well as different LPS analogues, and whether or not the structure of LPS affects its interaction with the CD14-TLR4-MD-2 cluster. Is it possible that the 'shape' of LPS induces the formation of different receptor clusters, and thus a different immune response? In the present study, we demonstrate using biochemical as well as fluorescence-imaging techniques that different LPS analogues trigger the recruitment of different receptors within microdomains. The composition of each receptor cluster as well as the number of TLR4 molecules that are recruited within the cluster seem to determine whether an immune response will be induced or inhibited.
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Key Words
- innate recognition
- lipopolysaccharide (lps)
- lipopolysaccharide-activation cluster toll-like receptor 4 (tlr4)
- cho, chinese-hamster ovary
- cxcr4, chemokine receptor 4
- frap, fluorescence recovery after photobleaching
- fret, fluorescence resonance energy transfer
- gdf5, growth-differentiation factor 5
- gm-1, monosialoganglioside
- hrp, horseradish peroxidase
- hsp, heat-shock protein
- iκb, inhibitory κb
- jnk, c-jun n-terminal kinase
- lps, lipopolysaccharide
- mab, monoclonal antibody
- mapk, mitogen-activated protein kinase
- meb, membrane-extraction buffer
- mhc, major histocompatibility complex
- mnc, mononuclear cell
- nf-κb, nuclear factor κb
- pbs-t, pbs with tween 20
- pla, penta-acyl lipid a
- sapk, stress-activated protein kinase
- tlr, toll-like receptor
- tnf-α, tumour necrosis factor α
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Affiliation(s)
- Martha Triantafilou
- Infection and Immunity Group, School of Life Sciences, University of Sussex, JMS Building, Falmer, Brighton BN1 9QG, UK.
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