Cell-free reconstitution of vacuole membrane fragmentation reveals regulation of vacuole size and number by TORC1.

Détails

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Etat: Public
Version: de l'auteur⸱e
ID Serval
serval:BIB_5E09E0E28CEC
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Cell-free reconstitution of vacuole membrane fragmentation reveals regulation of vacuole size and number by TORC1.
Périodique
Molecular Biology of the Cell
Auteur⸱e⸱s
Michaillat L., Baars T.L., Mayer A.
ISSN
1939-4586 (Electronic)
ISSN-L
1059-1524
Statut éditorial
Publié
Date de publication
2012
Volume
23
Numéro
5
Pages
881-895
Langue
anglais
Résumé
Size and copy number of organelles are influenced by an equilibrium of membrane fusion and fission. We studied this equilibrium on vacuoles-the lysosomes of yeast. Vacuole fusion can readily be reconstituted and quantified in vitro, but it had not been possible to study fission of the organelle in a similar way. Here we present a cell-free system that reconstitutes fragmentation of purified yeast vacuoles (lysosomes) into smaller vesicles. Fragmentation in vitro reproduces physiological aspects. It requires the dynamin-like GTPase Vps1p, V-ATPase pump activity, cytosolic proteins, and ATP and GTP hydrolysis. We used the in vitro system to show that the vacuole-associated TOR complex 1 (TORC1) stimulates vacuole fragmentation but not the opposing reaction of vacuole fusion. Under nutrient restriction, TORC1 is inactivated, and the continuing fusion activity then dominates the fusion/fission equilibrium, decreasing the copy number and increasing the volume of the vacuolar compartment. This result can explain why nutrient restriction not only induces autophagy and a massive buildup of vacuolar/lysosomal hydrolases, but also leads to a concomitant increase in volume of the vacuolar compartment by coalescence of the organelles into a single large compartment.
Mots-clé
Cell-Free System/chemistry, GTP-Binding Proteins/metabolism, Guanosine Triphosphate/chemistry, Guanosine Triphosphate/metabolism, Hydrolysis, Intracellular Membranes/metabolism, Intracellular Membranes/ultrastructure, Membrane Fusion, Protein Phosphatase 2/metabolism, Saccharomyces cerevisiae/chemistry, Saccharomyces cerevisiae/metabolism, Saccharomyces cerevisiae Proteins/antagonists & inhibitors, Saccharomyces cerevisiae Proteins/metabolism, Sirolimus/pharmacology, Transcription Factors/antagonists & inhibitors, Transcription Factors/metabolism, Vacuoles/chemistry, Vacuoles/metabolism, Vesicular Transport Proteins/metabolism
Pubmed
Web of science
Création de la notice
24/03/2012 9:43
Dernière modification de la notice
20/08/2019 14:16
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