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See detailGlycine receptor activation influences early cortical development
Avila Macaya, Ariel Salvatore ULg; Nguyen, Laurent ULg

Poster (2011, July 14)

The strychnine-sensitive glycine receptor (GlyR) is a member of the ligand-gated ion channel superfamily. In the adult, the GlyR is known to mediate fast inhibitory neurotransmission in the spinal cord ... [more ▼]

The strychnine-sensitive glycine receptor (GlyR) is a member of the ligand-gated ion channel superfamily. In the adult, the GlyR is known to mediate fast inhibitory neurotransmission in the spinal cord and in the brainstem. The GlyR has also been described in the embryonic cortex after embryonic day 19 (E19) (Flint et al., 1998) where it could participate in developmental processes, but its presence at earlier stages has not been documented. Since other neurotransmitter systems, i.e. GABA and its receptors, are known to be potent signals that control corticogenesis (Nguyen et al., 2001; Ik-Tsen et al., 2007), we wondered if glycine and its GlyR could also fulfill such a function. In this study, we analyze GlyR expression and its physiological function in the early development of the cortex using in vitro cultures of embryonic day 13 slices, patch-clamp and immunocytochemistry. [less ▲]

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See detailThe glycine receptor is functionally expressed in migratory interneurons and influences early cortical development
Avila Macaya, Ariel Salvatore ULg; Nguyen, Laurent ULg

Poster (2011)

The strychnine-sensitive glycine receptor (GlyR) is a member of the ligand-gated ion channel superfamily. In the adult, the GlyR is known to mediate fast inhibitory neurotransmission in the spinal cord ... [more ▼]

The strychnine-sensitive glycine receptor (GlyR) is a member of the ligand-gated ion channel superfamily. In the adult, the GlyR is known to mediate fast inhibitory neurotransmission in the spinal cord and in the brainstem. The GlyR has also been described in the embryonic cortex after embryonic day 19 (E19) (Flint et al., 1998) where it could participate in developmental processes, but its presence at earlier stages has not been documented. Since other neurotransmitter systems, i.e. GABA and its receptors, are known to be potent signals that control corticogenesis (Nguyen et al., 2001; Ik-Tsen et al., 2007), we wondered if glycine and its GlyR could also fulfill such a function. In this study, we analyze GlyR expression and its physiological function in the early development of the cortex using in vitro cultures of embryonic day 13 slices, patch-clamp, two photon microscopy and immunocytochemistry. [less ▲]

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See detailGlycine Receptor α2 Subunit Activation Promotes Cortical Interneuron Migration
Avila Macaya, Ariel Salvatore ULg; Vidal, Pia M; Dear, T Neil et al

in Cell Reports (2013)

Glycine receptors (GlyRs) are detected in the developing CNS before synaptogenesis, but their function remains elusive. This study demonstrates that functional GlyRs are expressed by embryonic cortical ... [more ▼]

Glycine receptors (GlyRs) are detected in the developing CNS before synaptogenesis, but their function remains elusive. This study demonstrates that functional GlyRs are expressed by embryonic cortical interneurons in vivo. Furthermore, genetic disruption of these receptors leads to interneuron migration defects. We discovered that extrasynaptic activation of GlyRs containing the α2 subunit in cortical interneurons by endogenous glycine activates voltage-gated calcium channels and promotes calcium influx, which further modulates actomyosin contractility to fine-tune nuclear translocation during migration. Taken together, our data highlight the molecular events triggered by GlyR α2 activation that control cortical tangential migration during embryogenesis. [less ▲]

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See detailGlycine receptors control the generation of projection neurons in the developing cerebral cortex
Avila, Ariel; Vidal, P.M.; Tielens, Sylvia ULg et al

in Cell Death & Differentiation (in press)

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See detailGlycine Triggers an Intracellular Calcium Influx in Oligodendrocyte Progenitor Cells Which Is Mediated by the Activation of Both the Ionotropic Glycine Receptor and Na+-Dependent Transporters
Belachew, Shibeshih ULg; Malgrange, Brigitte ULg; Rigo, Jean-Michel et al

in European Journal of Neuroscience (2000), 12(6), 1924-30

Using fluo-3 calcium imaging, we demonstrate that glycine induces an increase in intracellular calcium concentration ([Ca2+]i) in cortical oligodendrocyte progenitor (OP) cells. This effect results from a ... [more ▼]

Using fluo-3 calcium imaging, we demonstrate that glycine induces an increase in intracellular calcium concentration ([Ca2+]i) in cortical oligodendrocyte progenitor (OP) cells. This effect results from a calcium entry through voltage-gated calcium channels (VGCC), as it is observed only in OP cells expressing such channels, and it is abolished either by removal of calcium from the extracellular medium or by application of an L-type VGCC blocker. Glycine-triggered Ca2+ influx in OP cells actually results from an initial depolarization that is the consequence of the activation of both the ionotropic glycine receptor (GlyR) and Na+-dependent transporters, most probably the glycine transporters 1 (GLYT1) and/or 2 (GLYT2) which are colocalized in these cells. Through this GlyR- and transporter-mediated effect on OP intrcellular calcium concentration [Ca2+]i, glycine released by neurons may, as well as other neurotransmitters, serve as a signal between neurons and OP during development. [less ▲]

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See detailGlycogen synthase kinase-3 regulates mitochondrial outer membrane permeabilization and apoptosis by destabilization of MCL-1
Maurer, Ulrich; Charvet, Céline; Wagman, Allan et al

in Molecular Cell (2006), 21(6), 749-760

We investigated the role of glycogen synthase kinase-3 (GSK-3), which is inactivated by AKT, for its role in the regulation of apoptosis. Upon IL-3 withdrawal, protein levels of MCL-1 decreased but were ... [more ▼]

We investigated the role of glycogen synthase kinase-3 (GSK-3), which is inactivated by AKT, for its role in the regulation of apoptosis. Upon IL-3 withdrawal, protein levels of MCL-1 decreased but were sustained by pharmacological inhibition of GSK-3, which prevented cytochrome c release and apoptosis. MCL-1 was phosphorylated by GSK-3 at a conserved GSK-3 phosphorylation site (S159). S159 phosphorylation of MCL-1 was induced by IL-3 withdrawal or PI3K inhibition and prevented by AKT or inhibition of GSK-3, and it led to increased ubiquitinylation and degradation of MCLA. A phosphorylation-site mutant (MCL-1(S159A)), expressed in IL-3-dependent cells, showed enhanced stability upon IL-3 withdrawal and conferred increased protection from apoptosis compared to wild-type MCL-1. The results demonstrate that the control of MCLA stability by GSK-3 is an important mechanism for the regulation of apoptosis by growth factors, PI3K, and AKT. [less ▲]

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See detailGlycol chitosan improves the efficacy of intranasally administrated replication defective human adenovirus type 5 expressing glycoprotein D of bovine herpesvirus 1
Gogev, S.; de Fays, K.; Versali, Marie-France ULg et al

in Vaccine (2004), 22(15-16), 1946-1953

The ability of two soluble formulations, namely chitosan and glycol chitosan, when used as an intranasal adjuvant, to improve the immunogenicity of an intranasal human adenovirus type 5 replication ... [more ▼]

The ability of two soluble formulations, namely chitosan and glycol chitosan, when used as an intranasal adjuvant, to improve the immunogenicity of an intranasal human adenovirus type 5 replication defective expressing bovine herpesvirus 1 (BoHV-1) glycoprotein D based vaccine, was investigated in cattle. Their adjuvant effects on immune response by increasing clinical and especially virological protection against an intranasal BoHV-1 challenge were then evaluated. The best virological protection was obtained in calves immunized with the vaccine vector adjuvanted with glycol chitosan which decreased the challenge BoHV-1 virus excretion titres by 0.5-1.5 log when compared to those obtained in calves immunized with the vaccine vector alone or adjuvanted with chitosan. A slight difference in clinical scores was observed in calves immunized with the adjuvanted vaccine vector compared to calves immunized with the vaccine vector alone. The obtained data suggest that the tested soluble formulation of glycol chitosan has promising potential use as an intranasal adjuvant for recombinant viral vector vaccines in cattle. (C) 2003 Elsevier Ltd. All rights reserved. [less ▲]

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See detailGlycoprotein B cleavage is important for murid herpesvirus 4 to infect myeloid cells.
Glauser, Daniel L.; Milho, Ricardo; Frederico, Bruno et al

in Journal of Virology (2013)

Glycoprotein B (gB) is a conserved herpesvirus virion component implicated in membrane fusion. As with many - but not all - herpesviruses, the gB of murid herpesvirus 4 (MuHV-4) is cleaved into disulfide ... [more ▼]

Glycoprotein B (gB) is a conserved herpesvirus virion component implicated in membrane fusion. As with many - but not all - herpesviruses, the gB of murid herpesvirus 4 (MuHV-4) is cleaved into disulfide-linked subunits, apparently by furin. Preventing gB cleavage for some herpesviruses causes minor infection deficits in vitro, but what the cleavage contributes to host colonization has been unclear. To address this we mutated the furin cleavage site (R-R-K-R) of the MuHV-4 gB. Abolishing gB cleavage did not affect its expression levels, glycosylation or antigenic conformation. In vitro, mutant viruses entered fibroblasts and epithelial cells normally, but had a significant entry deficit in myeloid cells such as macrophages and bone marrow-derived dendritic cells. The deficit in myeloid cells was not due to reduced virion binding or endocytosis, suggesting that gB cleavage promotes infection at a post-endocytic entry step, presumably viral membrane fusion. In vivo, viruses lacking gB cleavage showed reduced lytic spread in the lungs. Alveolar epithelial cell infection was normal, but alveolar macrophage infection was significantly reduced. Normal long-term latency in lymphoid tissue was established nonetheless. [less ▲]

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See detailGlycoprotein B of Bovine Herpesvirus 4 Is a Major Component of the Virion, Unlike That of Two Other Gammaherpesviruses, Epstein-Barr Virus and Murine Gammaherpesvirus 68
Lomonte, P.; Filée, Patrice ULg; Lyaku, J. R. et al

in Journal of Virology (1997), 71(4), 3332-5

This study reports that in bovine herpesvirus 4, glycoprotein B (gB) is a heterodimer and a major component of the virion, unlike gBs of Epstein-Barr virus (gp110) and murine gammaherpesvirus 68, two ... [more ▼]

This study reports that in bovine herpesvirus 4, glycoprotein B (gB) is a heterodimer and a major component of the virion, unlike gBs of Epstein-Barr virus (gp110) and murine gammaherpesvirus 68, two other gammaherpesviruses. These are new characteristics with regard to the general features of gB in the Gammaherpesvirinae subfamily. [less ▲]

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See detailGlycoprotein B switches conformation during murid herpesvirus 4 entry.
Gillet, Laurent ULg; Colaco, Susanna; Stevenson, Philip G

in Journal of General Virology (The) (2008), 89(Pt 6), 1352-63

Herpesviruses are ancient pathogens that infect all vertebrates. The most conserved component of their entry machinery is glycoprotein B (gB), yet how gB functions is unclear. A striking feature of the ... [more ▼]

Herpesviruses are ancient pathogens that infect all vertebrates. The most conserved component of their entry machinery is glycoprotein B (gB), yet how gB functions is unclear. A striking feature of the murid herpesvirus 4 (MuHV-4) gB is its resistance to neutralization. Here, we show by direct visualization of infected cells that the MuHV-4 gB changes its conformation between extracellular virions and those in late endosomes, where capsids are released. Specifically, epitopes on its N-terminal cell-binding domain become inaccessible, whilst non-N-terminal epitopes are revealed, consistent with structural changes reported for the vesicular stomatitis virus glycoprotein G. Inhibitors of endosomal acidification blocked the gB conformation switch. They also blocked capsid release and the establishment of infection, implying that the gB switch is a key step in entry. Neutralizing antibodies could only partially inhibit the switch. Their need to engage a less vulnerable, upstream form of gB, because its fusion form is revealed only in endosomes, helps to explain why gB-directed MuHV-4 neutralization is so difficult. [less ▲]

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See detailGlycoprotein G isoforms from some alphaherpesviruses function as broad-spectrum chemokine binding proteins
Bryant, N. A.; Davis-Poynter, N.; Vanderplasschen, Alain ULg et al

in EMBO Journal (2003), 22

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See detailGlycoprotein H (gII/gp108) and glycoprotein L form a functional complex which plays a role in penetration, but not in attachment, of bovine herpesvirus 1.
van Drunen Littel-van den Hurk, S.; Khattar, S.; Tikoo, S. K. et al

in Journal of General Virology (The) (1996), 77 ( Pt 7)

The glycoproteins of bovine herpesvirus 1 (BHV-1) play important roles in the interactions between virions and target cells. A 108 kDa glycoprotein, designated gII or gp 108, has been identified by two ... [more ▼]

The glycoproteins of bovine herpesvirus 1 (BHV-1) play important roles in the interactions between virions and target cells. A 108 kDa glycoprotein, designated gII or gp 108, has been identified by two different panels of monoclonal antibodies. The gII- and gp 108-specific monoclonal antibodies were shown to react with the same protein, which was identified by N-terminal sequencing as the homologue of herpes simplex virus type 1 (HSV-1) gH. When BHV-1 gH was purified by immunoadsorbent chromatography, gL was co-purified. The gH-gL complex induced the production of antibodies that neutralized virus infectivity and inhibited virus penetration. Affinity-purified gH-gL did prevent penetration, but not attachment of BHV-1, which suggests that the gH-gL complex is essential for penetration of BHV-1 into susceptible cells. [less ▲]

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See detailGlycoprotein Ib and integrin alphaIIbbeta3 contribute to GPVI-dependent vWF-collagen induced thrombus formation under flow
Kuijpers, Marijke; Oury, Cécile ULg; Schulte, V. et al

in Journal of Thrombosis and Haemostasis [=JTH] (2003)

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See detailGlycoprotein L disruption reveals two functional forms of the murine gammaherpesvirus 68 glycoprotein H.
Gillet, Laurent ULg; May, Janet S; Colaco, Susanna et al

in Journal of Virology (2007), 81(1), 280-91

The herpesvirus glycoprotein H (gH) and gL associate to form a heterodimer that plays a central role in virus-driven membrane fusion. When archetypal alpha- or betaherpesviruses lack gL, gH misfolds and ... [more ▼]

The herpesvirus glycoprotein H (gH) and gL associate to form a heterodimer that plays a central role in virus-driven membrane fusion. When archetypal alpha- or betaherpesviruses lack gL, gH misfolds and progeny virions are noninfectious. In order to define the role that gL plays in gamma-2 herpesvirus infections, we disrupted its coding sequence in murine gammaherpesvirus-68 (MHV-68). MHV-68 lacking gL folded gH into a conformation antigenically distinct from the form that normally predominates on infected cells. gL-deficient virions bound less well than the wild type to epithelial cells and fibroblasts. However, they still incorporated gH and remained infectious. The cell-to-cell spread of gL-deficient viruses was remarkably normal, as was infection, dissemination, and latency establishment in vivo. Viral membrane fusion was therefore gL independent. The major function of gL appeared to be allowing gH to participate in cell binding prior to membrane fusion. This function was most important for the entry of MHV-68 virions into fibroblasts and epithelial cells. [less ▲]

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See detailGlycoprotein L sets the neutralization profile of murid herpesvirus 4.
Gillet, Laurent ULg; Alenquer, Marta; Glauser, Daniel L et al

in Journal of General Virology (The) (2009), 90(Pt 5), 1202-14

Antibodies readily neutralize acute, epidemic viruses, but are less effective against more indolent pathogens such as herpesviruses. Murid herpesvirus 4 (MuHV-4) provides an accessible model for tracking ... [more ▼]

Antibodies readily neutralize acute, epidemic viruses, but are less effective against more indolent pathogens such as herpesviruses. Murid herpesvirus 4 (MuHV-4) provides an accessible model for tracking the fate of antibody-exposed gammaherpesvirus virions. Glycoprotein L (gL) plays a central role in MuHV-4 entry: it allows gH to bind heparan sulfate and regulates fusion-associated conformation changes in gH and gB. However, gL is non-essential: heparan sulfate binding can also occur via gp70, and the gB-gH complex alone seems to be sufficient for membrane fusion. Here, we investigated how gL affects the susceptibility of MuHV-4 to neutralization. Immune sera neutralized gL(-) virions more readily than gL(+) virions, chiefly because heparan sulfate binding now depended on gp70 and was therefore easier to block. However, there were also post-binding effects. First, the downstream, gL-independent conformation of gH became a neutralization target; gL normally prevents this by holding gH in an antigenically distinct heterodimer until after endocytosis. Second, gL(-) virions were more vulnerable to gB-directed neutralization. This covered multiple epitopes and thus seemed to reflect a general opening up of the gH-gB entry complex, which gL again normally restricts to late endosomes. gL therefore limits MuHV-4 neutralization by providing redundancy in cell binding and by keeping key elements of the virion fusion machinery hidden until after endocytosis. [less ▲]

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See detailLa glycoprotéine gE de l'herpèsvirus bovin de type 1 et les nouveaux vaccins marqués
Schynts, Frédéric; Lemaire, Mylène; Baranowski, Eric et al

in Annales de Médecine Vétérinaire (1998), 142

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See detailLes glycoprotéines des herpèsvirus bovins 1 et 4
Thiry, Etienne ULg; Baranowski, Eric; Lomonte, Patrick et al

in El Hassane Diop, P.; Kaeckenbeeck, A. (Eds.) Biotechnologies du diagnostic et de la prévention des maldies animales (1994)

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See detailLes glycoproteines placentaires chez les mammiferes
Clerget, E.; Melo de Sousa, Noelita ULg; Bella, Amina ULg et al

in Annales d'Endocrinologie (2008), 69

Placental tissue exhibits a typical glycosylation pattern, which differs from that observed in the pituitary gland. Depending to the species and pregnancy period, the placenta synthesizes diverse ... [more ▼]

Placental tissue exhibits a typical glycosylation pattern, which differs from that observed in the pituitary gland. Depending to the species and pregnancy period, the placenta synthesizes diverse glycoproteins, some of which have significant hormonal activity, others being detected in maternal circulation. Thus, these molecules are of interest both from a fundamental and clinical point of view. Among the mammalian placental glycoproteins currently recognized, chorionic gonadotrophins from primates and Equidae, placental lactogen from bovines and the pregnancy-associated glycoproteins from ruminant species are particularly noteworthy. The diversity of saccharidic structures leads to multiple forms of placental glycoproteins exhibiting distinct structural and biological properties. For instance, concerning the chorionic gonadotrophins, the association of both alpha and beta subunits is essential for the binding of the hormone to specific receptors. Moreover, the N-linked oligossacharides are required for the activation of effectors systems. Bovine placental lactogen is a glycosylated hormone, exhibiting somatotropin- and prolactin-like activities. Several N-glycosylation sites confer to pregnancy-associated glycoproteins a long half-life (8-10 days) in maternal circulation. Assay of these molecules can be used for routine early pregnancy diagnosis and the follow-up of embryonic and fetal mortalities. [less ▲]

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