Relevant bibliographies by topics / Vpr extracellulaire

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  4. Conference papers

Academic literature on the topic 'Vpr extracellulaire'

Author: Grafiati
Published: 4 June 2021
Last updated: 1 February 2022

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Journal articles on the topic "Vpr extracellulaire"

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Lupescu, Adrian, C. Thomas Bock, Philipp A. Lang, Susanne Aberle, Heike Kaiser, Reinhard Kandolf, and Florian Lang. "Phospholipase A2 Activity-Dependent Stimulation of Ca2+ Entry by Human Parvovirus B19 Capsid Protein VP1." Journal of Virology 80, no. 22 (September 6, 2006): 11370–80. http://dx.doi.org/10.1128/jvi.01041-06.

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ABSTRACT Recent reports demonstrated an association of human parvovirus B19 with inflammatory cardiomyopathy (iCMP), which is accompanied by endothelial dysfunction. As intracellular Ca2+ activity is a key regulator of cell function and participates in mechanisms leading to endothelial dysfunction, the present experiments explored the effects of the B19 capsid proteins VP1 and VP2. A secreted phospholipase A2 (PLA2)-like activity has been located in the VP1 unique region of the B19 minor capsid protein. As PLA2 has recently been shown to activate the store-operated or capacitative Ca2+ channel ICRAC, we analyzed the impact of the viral PLA2 motif on Ca2+ entry. We cloned the VP1 and VP2 genes isolated from a patient suffering from fatal B19 iCMP into eukaryotic expression vectors. We also generated a B19 replication-competent plasmid to demonstrate PLA2 activity under the control of the complete B19 genome. After the transfection of human endothelial cells (HMEC-1), cytosolic Ca2+ activity was determined by utilizing Fura-2 fluorescence. VP1 and VP2 expression did not significantly modify basal cytosolic Ca2+ activity or the decline of cytosolic Ca2+ activity following the removal of extracellular Ca2+. However, expression of VP1 and of the full-length B19 clone, but not of VP2, significantly accelerated the increase of cytosolic Ca2+ activity following the readdition of extracellular Ca2+ in the presence of thapsigargin, indicating an activation of ICRAC. The effect of VP1 was mimicked by the PLA2 product lysophosphatidylcholine and abolished by an inactivating mutation of the PLA2-encoding region of the VP1 gene. Our observations point to the activation of Ca2+ entry by VP1 PLA2 activity, an effect likely participating in the pathophysiology of B19 infection.
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2

Dieye, Yakhya, Arjan J. W. Hoekman, Florence Clier, Vincent Juillard, Hein J. Boot, and Jean-Christophe Piard. "Ability of Lactococcus lactis To Export Viral Capsid Antigens: a Crucial Step for Development of Live Vaccines." Applied and Environmental Microbiology 69, no. 12 (December 2003): 7281–88. http://dx.doi.org/10.1128/aem.69.12.7281-7288.2003.

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ABSTRACT Thefood grade bacterium Lactococcus lactis is a potential vehicle for protein delivery in the gastrointestinal tract. As a model, we constructed lactococcal strains producing antigens of infectious bursal disease virus (IBDV). IBDV infects chickens and causes depletion of B-lymphoid cells in the bursa of Fabricius and subsequent immunosuppression, morbidity, or acute mortality. The two major IBDV antigens, i.e., VP2 and VP3, that form the viral capsid were expressed and targeted to the cytoplasm, the cell wall, or the extracellular compartment of L. lactis. Whereas VP3 was successfully targeted to the three compartments by the use of relevant expression and export vectors, VP2 was recalcitrant to export, thus confirming the difficulty of translocating naturally nonsecreted proteins across the bacterial membrane. This defect could be partly overcome by fusing VP2 to a naturally secreted protein (the staphylococcal nuclease Nuc) that carried VP2 through the membrane. Lactococcal strains producing Nuc-VP2 and VP3 in various bacterial compartments were administered orally to chickens. The chickens did not develop any detectable immune response against VP2 and VP3 but did exhibit an immune response against Nuc when Nuc-VP2 was anchored to the cell wall of lactococci.
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3

Sankovich, Sonia E., Daniela Koleski, Jonathan Baell, Barry Matthews, Ahmed A. Azad, and Ian G. Macreadie. "Design and Assay of Inhibitors of HIV-1 Vpr Cell Killing and Growth Arrest Activity Using Microbial Assay Systems." Journal of Biomolecular Screening 3, no. 4 (June 1998): 299–304. http://dx.doi.org/10.1177/108705719800300409.

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Viral protein R (Vpr), one of the accessory gene products encoded by the human immunodeficiency virus type 1 (HIV-1) genome, has a number of functions, including causing a growth arrest of HIV-1-infected cells and possibly the death of uninfected bystander cells. In microbial assay systems, the C-terminal portion of Vpr can cause cell death when added externally, and when expressed in yeast it causes growth arrest. In this study we have sought to obtain inhibitors of the Vpr functions that affect the microbial systems. Our first approach employed peptide display, which identified a number of sequences, including a heptapeptide sequence, GETRAPL, involved in binding to the C-terminus of Vpr. To determine whether GETRAPL could block the extracellular cytocidal activity of Vpr, the heptapeptide was synthesized and found to have some blocking activity in microbial assays. A second approach led to the finding that melittin inhibitors had activity against Vpr extracellular activities. In a third approach, compounds were tested against the Vpr-induced growth arrest. A number of compounds were found to abrogate the growth arrest, and some also inhibited Vpr's extracellular activity.
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Piller, SC. "Effect of extracellular HIV-1 Vpr protein in vitro." Journal of Neurovirology 7, no. 2 (January 2001): 183–84. http://dx.doi.org/10.1080/13550280152058843.

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Huang, VC Bond, M.-B. "Effect of extracellular HIV-1 Vpr protein in vitro." Journal of Neurovirology 7, no. 2 (January 2001): 184–85. http://dx.doi.org/10.1080/13550280152058852.

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6

Lee, Woonghee, Ronnie O. Frederick, Marco Tonelli, and Ann C. Palmenberg. "Solution NMR Determination of the CDHR3 Rhinovirus-C Binding Domain, EC1." Viruses 13, no. 2 (January 22, 2021): 159. http://dx.doi.org/10.3390/v13020159.

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Cadherin Related Family Member 3 (CDHR3) is the identified and required cellular receptor for all virus isolates in the rhinovirus-C species (RV-C). Cryo-EM determinations recently resolved the atomic structure of RV-C15a, and subsequently, a complex of this virus bound to CDHR3 extracellular domain 1 (EC1), the N-terminal portion of this receptor responsible for virus interactions. The EC1 binds to a hypervariable sequence footprint on the virus surface, near the 3-fold axis of icosahedral symmetry. The key contacts involve discontinuous residues from 3 viral proteins, VP1, VP2 and VP3. That single cryo-EM EC1 structure, however, could not resolve whether the virus-receptor interface was structurally adaptable to accommodate multiple virus sequences. We now report the solution NMR determination of CDHR3 EC1, showing that this protein, in fact, is mostly inflexible, particularly in the virus-binding face. The new, higher resolution dataset identifies 3 cis-Pro residues in important loop regions, where they can influence both rigidity and overall protein conformation. The data also provide clarification about the residues involved in essential calcium ion binding, and a potential CDHR3 surface groove feature that may be involved in native protein interactions with cellular partners.
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Sun, Yingyuan, Kelly Watters, Marchel G. Hill, Qianglin Fang, Yue Liu, Richard J. Kuhn, Thomas Klose, Michael G. Rossmann, and Ann C. Palmenberg. "Cryo-EM structure of rhinovirus C15a bound to its cadherin-related protein 3 receptor." Proceedings of the National Academy of Sciences 117, no. 12 (March 9, 2020): 6784–91. http://dx.doi.org/10.1073/pnas.1921640117.

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Infection byRhinovirus-C(RV-C), a species of PicornaviridaeEnterovirus, is strongly associated with childhood asthma exacerbations. Cellular binding and entry by all RV-C, which trigger these episodes, is mediated by the first extracellular domain (EC1) of cadherin-related protein 3 (CDHR3), a surface cadherin-like protein expressed primarily on the apical surfaces of ciliated airway epithelial cells. Although recombinant EC1 is a potent inhibitor of viral infection, there is no molecular description of this protein or its binding site on RV-C. Here we present cryo-electron microscopy (EM) data resolving the EC1 and EC1+2 domains of human CDHR3 complexed with viral isolate C15a. Structure-suggested residues contributing to required interfaces on both EC1 and C15a were probed and identified by mutagenesis studies with four different RV-C genotypes. In contrast to most other rhinoviruses, which bind intercellular adhesion molecule 1 receptors via a capsid protein VP1-specific fivefold canyon feature, the CDHR3 EC1 contacts C15a, and presumably all RV-Cs, in a unique cohesive footprint near the threefold vertex, encompassing residues primarily from viral protein VP3, but also from VP1 and VP2. The EC1+2 footprint on C15a is similar to that of EC1 alone but shows that steric hindrance imposed by EC2 would likely prevent multiprotein binding by the native receptor at any singular threefold vertex. Definition of the molecular interface between the RV-Cs and their receptors provides new avenues that can be explored for potential antiviral therapies.
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8

Patel, Charvi A., Muhammad Mukhtar, and Roger J. Pomerantz. "Human Immunodeficiency Virus Type 1 Vpr Induces Apoptosis in Human Neuronal Cells." Journal of Virology 74, no. 20 (October 15, 2000): 9717–26. http://dx.doi.org/10.1128/jvi.74.20.9717-9726.2000.

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ABSTRACT Human immunodeficiency virus type 1 (HIV-1) infection of the central nervous system (CNS) causes AIDS dementia complex (ADC) in certain infected individuals. Recent studies have suggested that patients with ADC have an increased incidence of neuronal apoptosis leading to neuronal dropout. Of note, a higher level of the HIV-1 accessory protein Vpr has been detected in the cerebrospinal fluid of AIDS patients with neurological disorders. Moreover, extracellular Vpr has been shown to form ion channels, leading to cell death of cultured rat hippocampal neurons. Based on these previous findings, we first investigated the apoptotic effects of the HIV-1 Vpr protein on the human neuronal precursor NT2 cell line at a range of concentrations. These studies demonstrated that apoptosis induced by both Vpr and the envelope glycoprotein, gp120, occurred in a dose-dependent manner compared to protein treatment with HIV-1 integrase, maltose binding protein (MBP), and MBP-Vpr in the undifferentiated NT2 cells. For mature, differentiated neurons, apoptosis was also induced in a dose-dependent manner by both Vpr and gp120 at concentrations ranging from 1 to 100 ng/ml, as demonstrated by both the terminal deoxynucleotidyltransferase (Tdt)-mediated dUTP-biotin nick end labeling and Annexin V assays for apoptotic cell death. In order to clarify the intracellular pathways and molecular mechanisms involved in Vpr- and gp120-induced apoptosis in the NT2 cell line and differentiated mature human neurons, we then examined the cellular lysates for caspase-8 activity in these studies. Vpr and gp120 treatments exhibited a potent increase in activation of caspase-8 in both mature neurons and undifferentiated NT2 cells. This suggests that Vpr may be exerting selective cytotoxicity in a neuronal precursor cell line and in mature human neurons through the activation of caspase-8. These data represent a characterization of Vpr-induced apoptosis in human neuronal cells, and suggest that extracellular Vpr, along with other lentiviral proteins, may increase neuronal apoptosis in the CNS. Also, identification of the intracellular activation of caspase-8 in Vpr-induced apoptosis of human neuronal cells may lead to therapeutic approaches which can be used to combat HIV-1-induced neuronal apoptosis in AIDS patients with ADC.
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Ghosh, Abhrajyoti, Krishanu Chakrabarti, and Dhrubajyoti Chattopadhyay. "Cloning of feather-degrading minor extracellular protease from Bacillus cereus DCUW: dissection of the structural domains." Microbiology 155, no. 6 (June 1, 2009): 2049–57. http://dx.doi.org/10.1099/mic.0.027573-0.

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Bacterial extracellular proteases play an important role in cell survival and cell–cell communication. A high-molecular-mass minor extracellular protease (Vpr) from a feather-degrading bacterium, Bacillus cereus DCUW, has been reported by our laboratory. In the present study, we cloned and expressed Vpr in Escherichia coli. Complete nucleotide sequencing of this gene predicted that the protease is a member of the serine protease family, and smart domain analysis revealed that the protease consists of an N-terminal signal sequence for secretion, a subtilisin_N sequence that is a signature for N-terminal processing, a catalytic S_8 peptidase domain, and finally a long C-terminal protease-associated (PA) region containing nine intrinsically disordered subdomains. Four truncated constructs of the Vpr protease were cloned and expressed in E. coli. We found that the catalytic domain (amino acid residues 172–583) is sufficient for protease activity. Maturation of the Vpr protease needed both N-terminal and C-terminal processing. We have demonstrated that the oligomerization property is associated with the C-terminal protease-associated domain and also shown that the substrate-binding specificity to raw feather resides in this domain.
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10

Mishra, Sasmita, Jyoti P. Mishra, and Ashok Kumar. "Activation of JNK-dependent Pathway Is Required for HIV Viral Protein R-induced Apoptosis in Human Monocytic Cells." Journal of Biological Chemistry 282, no. 7 (December 11, 2006): 4288–300. http://dx.doi.org/10.1074/jbc.m608307200.

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Human immunodeficiency virus (HIV) accessory protein viral protein R (Vpr) plays a key role in virus replication and induces cell cycle arrest and apoptosis in various cell types including T cells and neuronal and tumor cells following infection with Vpr-expressing HIV isolates or exposure to the extracellular Vpr protein. The C-terminal Vpr peptide encompassing amino acids 52–96 (Vpr-(52–96)) is required for exerting the apoptotic effects, whereas the N-terminal Vpr-(1–45) peptide is responsible for virus transcription. We demonstrate that Vpr-(52–96) induced apoptosis in human promonocytic THP-1 cells and primary monocytes through the mitochondrial pathway in a caspase-dependent manner. To understand the regulation of Vpr-induced apoptosis, we investigated the signaling pathways, particularly the MAPKs, and the transcription factors involved. Although both Vpr-(52–96) and Vpr-(1–45) peptides induced phosphorylation of all the three members of the MAPKs, Vpr-(52–96)-activated JNK selectively induced apoptosis in monocytic cells through the mitochondrial pathway as determined by using JNK inhibitors SP60025, dexamethasone, curcumin, and JNK-specific small interfering RNAs. Furthermore Vpr-(52–96)-induced apoptosis was mediated by inhibition of downstream antiapoptotic Bcl2 and c-IAP1 genes whose expression could be restored following pretreatment with JNK-specific inhibitors. Overall the results suggest that Vpr-(52–96)-activated JNK plays a key role in inducing apoptosis through the down-regulation of antiapoptotic Bcl2 and c-IAP1 genes.
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Dissertations / Theses on the topic "Vpr extracellulaire"

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Le, Buanec Hélène. "Contribution au développement de vaccins visant à corriger l'immunosuppression stromale induite par les tissus infectés par le VIH-1 et par les tumeurs dépendantes de la protéine E7 du papillomavirus de type 16." Paris 6, 2005. http://www.theses.fr/2005PA066060.

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Xiao, Yong. "Molecular and functional studies of human immunodeficiency virus type 1 accessory protein." Thèse, 2006. http://hdl.handle.net/1866/15819.

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Book chapters on the topic "Vpr extracellulaire"

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Abo-El-Dahab, M. K., M. A. El-Goorani, and S. A. El-Kazazz. "In Vitro Production of Extracellular Polysaccharides by Erwinia Carotovora Var. Carotovora and Erwinia Carotovora Var. Atroseptica." In Plant Pathogenic Bacteria, 237–43. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-3555-6_36.

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Conference papers on the topic "Vpr extracellulaire"

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Powling, M. J., and R. M. Hardisty. "THE DEPENDENCE OF PLATELET ATP SECRETION IN RESPONSE TO VARIOUS AGONISTS ON Ca2+ MOBILIZATION AND AGGREGATION IN QUIN 2 LOADED PLATELETS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644676.

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Thrombin (0.O5 and 0.5 u/ml), ADP (10 uM), PAF. (30 nM), vasopressin (vp, 0.018 u/m1 ), arachidonate (AA, 10 uM), U46619 (0.125 ug/ml) and A23187 (2OO nM) induce aggregation ATP secretion, TxB2 generation and a rapid elevation of intracellular calcium (Ca2+i) concentration provided the medium contains 1 mM extracellular Ca2+. Phorbol ester (TPA) induces aggregation and secretion with no alteration in [Ca2+i]. Pre-incubation with Fab fragments of Ml48, a monoclonal antibody against GPIIb/lIIa, completely abolished aggregation in response to all agonists without affecting Ca2+i flux. ADP and A23187-induced secretion was completely abolished by M148 Fab while that induced by VP, PAF, U46619, AA, thrombin and TPA was inhibited by 70%, 70%, 30%, 25%, 25% and 10% respectively.In the presence of 1 mM EGTA (Ca2+o <100 nM), aggregation was again abolished and the Ca2+i fluxes were about 10-20% of those in the presence of 1 mM Ca2+ o. ADP and A23187 again induced no secretion, but 0.05 u/ml thrombin, PAF, VP, U46619, AA, 0.5 u/ml thrombin and TPA induced respectively 6%, 8%, 12%, 30%, 40%, 57% and 85% of control (1 mM Ca2+ o) levels. Addition of Ml48 Fab and EGTA together had no greater effect than EGTA alone.At the concentrations used, ADP and A23187 are thus completely dependent on aggregation for the induction of ATP secretion, while TPA and thrombin (0.5 u.ml) can actlargely independently of both aggregation and changes in[Ca2+ i]. Low concentrations of thrombin induce secretion in the absence of aggregation provided the stimulated [Ca2+i] is sufficiently high (ie greater than that seen with <100 nM Ca2+ o). VP and PAF appear to be more dependent on aggregation for their secretory responses, while U46619 and AA are more dependent on stimulated [Ca2+i].
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Moffat, Katrina J., and D. Euan MacIntyre. "REGULATION OF RECEPTOR-OPERATED Ca2− CHANNEL OPENING IN HUMAN PLATELETS." In XIth International Congress on Thrombosis and Haemostasis. Schattauer GmbH, 1987. http://dx.doi.org/10.1055/s-0038-1644677.

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Agonist-induced elevation of the platelet intracellular free Ca2+ concentration ([Ca2−]i), as monitored using quin2, is not electrically mediated and is attenuated by removal of extracellular Ca2− and by lanthanides (e.g Gd3−).Collectively these data suggest that elevation of [Ca2−]i in platelets derives in part via influx of external Ca2−presumably through a receptor-operated Ca2− channel (ROC). Hal lam & Rink (FEBS Lett. 186: 175: 1985) showed that Mn2−also enters platelets via these ROC. To investigate the possible regulatory mechanisms that govern ROC status, we utilized quin2-labelled human platelets suspended in a Ca2+-free Hepes buffered Tyrodes solution, and monitored agonist-induced Mn2+-mediated quenching of quin2 fluorescence as an index of ROC opening.Thrombin (Th, 0.01-1 U/ml), Vasopressin (VP, 10-1000 nM) and the TxA2-mitnetic, EP171 (1-100 nM) all induced ROC opening which occurred rapidly (<30s), was maximal within 30-60s and thereafter declined. Gd3+ (≤2 mM) markedly impaired this Mn2ࢤ-mediated quenching of quin2 fluorescence induced by all 3 agonists. The adenylate cyclase stimulant PGD2 (3-3000 nM) and the guanylate cyclase stimulant sodium nitroprusside (0.01-10 μM) impaired ROC opening induced by Th (0.5 U/ml), VP (100 nM) and EP171 (25 nM) whether added to platelets ≤120sbefore or 30s after the agonists. In contrast, agents that selectively antagonize, at the receptor level, the effects of VP (e.g. d(CH2)5Tyr Me AVP, 10 ¼H) or EP171 (e.g.EP092, 250nM), or that inhibit the action of Th(e.g. Hirudin 1 U/ml)only impaired ROC opening when added to platelets simultaneously with or before the agonist.These results indicate that, although initiated by agonist-receptor interaction, maintenance of the open state of ROC in human platelets does not require continued receptor occupancy or activation by agonist. Moreover, besides acting to impair the transduction processes initiated following occupancy by agonist of platelet Vi, TP and Thrombin receptors, cAMP-and cGMP-dependent reactions also can terminate or otherwise limit opening of ROC.
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