title: Regulation of lipid droplet dynamics in Saccharomyces cerevisiae depends on the Rab7-like Ypt7p, HOPS complex and V1-ATPase.
abstract: It has now been clearly shown that lipid droplets (LDs) play a dynamic role in the cell. This was reinforced by LD proteomics which suggest that a significant number of trafficking proteins are associated with this organelle. Using microscopy, we showed that LDs partly co-localize with the vacuole in S. cerevisiae. Immunoblot experiments confirmed the association of the vacuolar Rab GTPase Rab7-like Ypt7p with LDs. We observed an increase in fatty acid content and LD number in ypt7Δ mutant and also changes in LD morphology and intra LD fusions, revealing a direct role for Ypt7p in LD dynamics. Using co-immunoprecipitation, we isolated potential Ypt7p partners including, Vma13p, the H subunit of the V1 part of the vacuolar (H+) ATPase (V-ATPase). Deletion of the VMA13 gene, as well as deletion of three other subunits of the V1 part of the V-ATPase, also increased the cell fatty acid content and LD number. Mutants of the Homotypic fusion and vacuole protein sorting (HOPS) complex showed similar phenotypes. Here, we demonstrated that LD dynamics and membrane trafficking between the vacuole and LDs are regulated by the Rab7-like Ypt7p and are impaired when the HOPS complex and the V1 domain of the V-ATPase are defective.
authors.affiliation: Institut Jean-Pierre Bourgin IJPB, UMR 1318 INRA, Saclay Plant Sciences, route de St Cyr (RD 10), 78026, Versailles cedex, France Institut Jean-Pierre Bourgin IJPB, UMR 1318 AgroParisTech, route de St Cyr (RD 10), 78026, Versailles cedex, France isabelle.bouchez@versailles.inra.fr.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Bouchez
authors.affiliation: Institut Jean-Pierre Bourgin IJPB, UMR 1318 INRA, Saclay Plant Sciences, route de St Cyr (RD 10), 78026, Versailles cedex, France Institut Jean-Pierre Bourgin IJPB, UMR 1318 AgroParisTech, route de St Cyr (RD 10), 78026, Versailles cedex, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Pouteaux
authors.affiliation: Institut Jean-Pierre Bourgin IJPB, UMR 1318 INRA, Saclay Plant Sciences, route de St Cyr (RD 10), 78026, Versailles cedex, France Institut Jean-Pierre Bourgin IJPB, UMR 1318 AgroParisTech, route de St Cyr (RD 10), 78026, Versailles cedex, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Canonge
authors.affiliation: Institut Jean-Pierre Bourgin IJPB, UMR 1318 INRA, Saclay Plant Sciences, route de St Cyr (RD 10), 78026, Versailles cedex, France Institut Jean-Pierre Bourgin IJPB, UMR 1318 AgroParisTech, route de St Cyr (RD 10), 78026, Versailles cedex, France.
authors.forename: Mélanie
authors.initials: M
authors.lastname: Genet
authors.affiliation: Institut Jean-Pierre Bourgin IJPB, UMR 1318 INRA, Saclay Plant Sciences, route de St Cyr (RD 10), 78026, Versailles cedex, France Institut Jean-Pierre Bourgin IJPB, UMR 1318 AgroParisTech, route de St Cyr (RD 10), 78026, Versailles cedex, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Chardot
authors.affiliation: MICALIS PAPPSO, UMR 1319 INRA, Domaine de Vilvert 78352, Jouy-en-Josas cedex, France MICALIS PAPPSO, UMR 1319 AgroParisTech, Domaine de Vilvert 78352, Jouy-en-Josas cedex, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Guillot
authors.affiliation: Institut Jean-Pierre Bourgin IJPB, UMR 1318 INRA, Saclay Plant Sciences, route de St Cyr (RD 10), 78026, Versailles cedex, France Institut Jean-Pierre Bourgin IJPB, UMR 1318 AgroParisTech, route de St Cyr (RD 10), 78026, Versailles cedex, France.
authors.forename: Marine
authors.initials: M
authors.lastname: Froissard
keywords: Lipid droplet; Rab GTPase; V-ATPase; Vacuole; Ypt7p