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Neuhaus, Jean-Marc

Nom
Neuhaus, Jean-Marc
Affiliation principale
Fonction
Professeur.e émérite
Email
jean-marc.neuhaus@unine.ch
Identifiants
https://libra.unine.ch/handle/123456789/300
_
0000-0003-3288-101X

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  • Publication
    Métadonnées seulement
    The internal propeptide of the ricin precursor carries a sequence-specific determinant for vacuolar sorting
    (2001)
    Frigerio, Lorenzo
    ;
    Jolliffe, Nicholas A
    ;
    Di Cola, Alessandra
    ;
    Hernández Felipe, Doramys
    ;
    Paris, Nadine
    ;
    Neuhaus, Jean-Marc 
    ;
    Lord, J Michael
    ;
    Ceriotti, Aldo
    ;
    Roberts, Lynne M
    Ricin is a heterodimeric toxin that accumulates in the storage vacuoles of castor bean (Ricinus communis) endosperm. Proricin is synthesized as a single polypeptide precursor comprising the catalytic A chain and the Gal-binding B chain joined by a 12-amino acid linker propeptide. Upon arrival in the vacuole, the linker is removed. Here, we replicate these events in transfected tobacco (Nicotiana tabacum) leaf protoplasts. We show that the internal linker propeptide is responsible for vacuolar sorting and is sufficient to redirect the ricin heterodimer to the vacuole when fused to the A or the B chain. This internal peptide can also target two different secretory protein reporters to the vacuole. Moreover, mutation of the isoleucine residue within an NPIR-like motif of the propeptide affects vacuolar sorting in proricin and in the reconstituted A-B heterodimer. This is the first reported example of a sequence-specific vacuolar sorting signal located within an internal propeptide.
  • Publication
    Accès libre
    Regeneration of a lytic central vacuole and of neutral peripheral vacuoles can be visualized by green fluorescent proteins targeted to either type of vacuoles
    (2001)
    Di Sansebastiano, Gian Pietro
    ;
    Paris, Nadine
    ;
    Marc-Martin, Sophie 
    ;
    Neuhaus, Jean-Marc 
    Protein trafficking to two different types of vacuoles was investigated in tobacco (Nicotiana tabacum cv SR1) mesophyll protoplasts using two different vacuolar green fluorescent proteins (GFPs). One GFP is targeted to a pH-neutral vacuole by the C-terminal vacuolar sorting determinant of tobacco chitinase A, whereas the other GFP is targeted to an acidic lytic vacuole by the N-terminal propeptide of barley aleurain, which contains a sequence-specific vacuolar sorting determinant. The trafficking and final accumulation in the central vacuole (CV) or in smaller peripheral vacuoles differed for the two reporter proteins, depending on the cell type. Within 2 d, evacuolated (mini-) protoplasts regenerate a large CV. Expression of the two vacuolar GFPs in miniprotoplasts indicated that the newly formed CV was a lytic vacuole, whereas neutral vacuoles always remained peripheral. Only later, once the regeneration of the CV was completed, the content of peripheral storage vacuoles could be seen to appear in the CV of a third of the cells, apparently by heterotypic fusion.