Voici les éléments 1 - 10 sur 19
  • Publication
    Accès libre
    Expression of a glycosylated GFP as a bivalent reporter in exocytosis
    (2010)
    Paris, Nadine
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    Saint-Jean, Bruno
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    Faraco, Marianna
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    Krzeszowiec, Weronika
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    Dalessandro, Giuseppe
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    Di Sansebastiano, Gian Pietro
    The complex-type N-linked glycans of plants differ markedly in structure from those of animals. Like those of insects and mollusks they lack terminal sialic acid(s) and may contain an α-(1,3)-fucose (Fuc) linked to the proximal GlcNAc residue and/or a β-(1,2)-xylose (Xyl) residue attached to the proximal mannose (Man) of the glycan core. N-glycosylated GFPs were used in previous studies showing their effective use to report on membrane traffic between the ER and the Golgi apparatus in plant cells. In all these cases glycosylated tags were added at the GFP termini. Because of the position of the tag and depending on the sorting and accumulation site of these modified GFP, there is always a risk of processing and degradation, and this protein design cannot be considered ideal. Here, we describe the development of three different GFPs in which the glycosylation site is internally localized at positions 80, 133, or 172 in the internal sequence. The best glycosylation site was at position 133. This glycosylated GFPgl133 appears to be protected from undesired processing of the glycosylation site and represents a bivalent reporter for biochemical and microscopic studies. After experimental validation, we can conclude that amino acid 133 is an effective glycosylation site and that the GFPgl133 is a powerful tool for in vivo investigations in plant cell biology.
  • Publication
    Métadonnées seulement
    The Cytosolic Tail Dipeptide Ile-Met of the Pea Receptor BP80 Is Required for Recycling from the Prevacuole and for Endocytosis
    (2010)
    Saint-Jean, B.
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    Seveno-Carpentier, E.
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    Alcon, C.
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    Paris, Nadine
    Pea (Pisum sativum) BP80 is a vacuolar sorting receptor for soluble proteins and has a cytosolic domain essential for its intracellular trafficking between the trans-Golgi network and the prevacuole. Based on mammalian knowledge, we introduced point mutations in the cytosolic region of the receptor and produced chimeras of green fluorescent protein fused to the transmembrane domain of pea BP80 along with the modified cytosolic tails. By analyzing the subcellular location of these chimera, we found that mutating Glu-604, Asp-616, or Glu-620 had mild effects, whereas mutating the Tyr motif partially redistributed the chimera to the plasma membrane. Replacing both Ile-608 and Met-609 by Ala (IMAA) led to a massive redistribution of fluorescence to the vacuole, indicating that recycling is impaired. When the chimera uses the alternative route, the IMAA mutation led to a massive accumulation at the plasma membrane. Using Arabidopsis thaliana plants expressing a fluorescent reporter with the full-length sequence of At VSR4, we demonstrated that the receptor undergoes brefeldin A-sensitive endocytosis. We conclude that the receptors use two pathways, one leading directly to the lytic vacuole and the other going via the plasma membrane, and that the Ileu-608 Met-609 motif has a role in the retrieval step in both pathways.
  • Publication
    Métadonnées seulement
    Targeting of ProConA to the Plant Vacuole Depends on Its Nine Amino-Acid C-Terminal Propeptide
    (2005)
    Saint-Jore-Dupas, Claude
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    Gilbert, Marie-Agnès
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    Ramis, Catalina
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    Paris, Nadine
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    Kiefer-Meyer, Marie-Christine
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    Faye, Loic
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    Gomord, Véronique
  • Publication
    Métadonnées seulement
    Plant vacuoles. from biogenesis to function
    (2005) ;
    Paris, Nadine
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    Samaj, J. E.
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    Baluska, F. E.
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    Menzel, D.
  • Publication
    Métadonnées seulement
  • Publication
    Métadonnées seulement
    Arabidopsis mu A-adaptin interacts with the tyrosine motif of the vacuolar sorting receptor VSR-PS1
    (2004)
    Happel, Nicole
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    Honing, Stefan
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    Paris, Nadine
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    Robinson, David G
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    Holstein, Susanne E H
    In receptor-mediated transport pathways in mammalian cells, clathrin-coated vesicle (CCV) mu-adaptins are the main binding partners for the tyrosine sorting/internalization motif (YXXO). We have analyzed the function of the muA-adaptin, one of the five mu-adaptins from Arabidopsis thaliana, by pull-down assays and plasmon resonance measurements using its receptor-binding domain (RBD) fused to a histidine tag. We show that this adaptin is able to bind the consensus tyrosine motif YXXO from the pea vacuolar sorting receptor (VSR)-PS1, as well as from the mammalian trans-Golgi network (TGN)38 protein. Moreover, the tyrosine residue was revealed to be crucial for binding of the complete cytoplasmic tail of VSR-PS1 to the plant muA-adaptin. The trans-Golgi localization of the muA-adaptin strongly suggests its involvement in Golgi- to vacuole-trafficking events.
  • Publication
    Accès libre
    ArabidopsisµA-adaptin interacts with the tyrosine motif of the vacuolar sorting receptor VSR-PS1
    (2004)
    Happel, Nicole
    ;
    Höning, Stefan
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    Paris, Nadine
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    Robinson, David G.
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    Holstein, Suzanne E. H.
    In receptor-mediated transport pathways in mammalian cells, clathrin-coated vesicle (CCV) µ-adaptins are the main binding partners for the tyrosine sorting/internalization motif (YXXØ). We have analyzed the function of the µA-adaptin, one of the five µ-adaptins from Arabidopsis thaliana, by pull-down assays and plasmon resonance measurements using its receptor-binding domain (RBD) fused to a histidine tag. We show that this adaptin is able to bind the consensus tyrosine motif YXXØ from the pea vacuolar sorting receptor (VSR)-PS1, as well as from the mammalian trans-Golgi network (TGN)38 protein. Moreover, the tyrosine residue was revealed to be crucial for binding of the complete cytoplasmic tail of VSR-PS1 to the plant µA-adaptin. The trans-Golgi localization of the µA-adaptin strongly suggests its involvement in Golgi- to vacuole-trafficking events.
  • Publication
    Accès libre
    The Destination for Single-Pass Membrane Proteins Is Influenced Markedly by the Length of the Hydrophobic Domain
    (2002-05-02)
    Brandizzi, Federica
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    Frangne, Nathalie
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    Hawes, Chris
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    Paris, Nadine
    The tonoplast was proposed as a default destination of membrane-bound proteins without specific targeting signals. To investigate the nature of this targeting, we created type I fusion proteins with green fluorescent protein followed by the transmembrane domain of the human lysosomal protein LAMP1. We varied the length of the transmembrane domain from 23 to either 20 or 17 amino acids by deletion within the hydrophobic domain. The resulting chimeras, called TM23, TM20, and TM17, were expressed either transiently or stably in tobacco. TM23 clearly accumulated in the plasmalemma, as confirmed by immunoelectron microscopy. In contrast, TM17 clearly was retained in the endoplasmic reticulum, and TM20 accumulated in small mobile structures. The nature of the TM20-labeled compartments was investigated by coexpression with a marker localized mainly in the Golgi apparatus, AtERD2, fused to a yellow fluorescent protein. The strict colocalization of both fluorescent proteins indicated that TM20 accumulated in the Golgi apparatus. To further test the default destination of type I membrane proteins, green fluorescent protein was fused to the 19–amino acid transmembrane domain of the plant vacuolar sorting receptor BP-80. The resulting chimera also accumulated in the Golgi instead of in post-Golgi compartments, where native BP-80 localized. Additionally, when the transmembrane domain of BP-80 was lengthened to 22 amino acids, the reporter escaped the Golgi and accumulated in the plasma membrane. Thus, the tonoplast apparently is not a favored default destination for type I membrane proteins in plants. Moreover, the target membrane where the chimera concentrates is not unique and depends at least in part on the length of the membrane-spanning domain.
  • Publication
    Métadonnées seulement
    Plant cell biology
    (Oxford: Oxford University Press, 2002)
    Ceriotti, A.
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    Paris, Nadine
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    Hillmer, S.
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    Frigerio, L.
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    Vitale, A.
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    Robinson, D. G.
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    Lord, M. E.
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    Davey, J.
  • Publication
    Métadonnées seulement