Microautophagy of the nucleus coincides with a vacuolar diffusion barrier at nuclear-vacuolar junctions.

Détails

Ressource 1Télécharger: BIB_25EA5A83466C.P001.pdf (1823.19 [Ko])
Etat: Serval
Version: de l'auteur
ID Serval
serval:BIB_25EA5A83466C
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Microautophagy of the nucleus coincides with a vacuolar diffusion barrier at nuclear-vacuolar junctions.
Périodique
Molecular Biology of the Cell
Auteur(s)
Dawaliby R., Mayer A.
ISSN
1939-4586 (Electronic)
ISSN-L
1059-1524
Statut éditorial
Publié
Date de publication
2010
Volume
21
Numéro
23
Pages
4173-4183
Langue
anglais
Résumé
Nuclei bind yeast vacuoles via nucleus-vacuole (NV) junctions. Under nutrient restriction, NV junctions invaginate and release vesicles filled with nuclear material into vacuoles, resulting in piecemeal microautophagy of the nucleus (PMN). We show that the electrochemical gradient across the vacuolar membrane promotes invagination of NV junctions. Existing invaginations persist independently of the gradient, but final release of PMN vesicles requires again V-ATPase activity. We find that NV junctions form a diffusion barrier on the vacuolar membrane that excludes V-ATPase but is enriched in the VTC complex and accessible to other membrane-integral proteins. V-ATPase exclusion depends on the NV junction proteins Nvj1p,Vac8p, and the electrochemical gradient. It also depends on factors of lipid metabolism, such as the oxysterol binding protein Osh1p and the enoyl-CoA reductase Tsc13p, which are enriched in NV junctions, and on Lag1p and Fen1p. Our observations suggest that NV junctions form in two separable steps: Nvj1p and Vac8p suffice to establish contact between the two membranes. The electrochemical potential and lipid-modifying enzymes are needed to establish the vacuolar diffusion barrier, invaginate NV junctions, and form PMN vesicles.
Mots-clé
Autophagy, Carrier Proteins/metabolism, Cell Nucleus/physiology, Cell Nucleus/ultrastructure, Cytoplasmic Vesicles/metabolism, Diffusion, Flap Endonucleases/metabolism, Intracellular Membranes/physiology, Intracellular Membranes/ultrastructure, Membrane Proteins/metabolism, Oxidoreductases Acting on CH-CH Group Donors/metabolism, Proton-Motive Force, Receptors, Cytoplasmic and Nuclear/metabolism, Saccharomyces cerevisiae Proteins/metabolism, Vacuolar Proton-Translocating ATPases/metabolism, Vacuoles/physiology, Vacuoles/ultrastructure, Vesicular Transport Proteins/metabolism, Yeasts
Pubmed
Web of science
Création de la notice
27/01/2012 11:24
Dernière modification de la notice
03/03/2018 15:05
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