Regulation of lipid droplet dynamics in Saccharomyces cerevisiae depends on the Rab7-like Ypt7p, HOPS complex and V1-ATPase.

Isabelle Bouchez-Mahiout (1) , Marie Pouteaux (1) , Michel Canonge (1) , Mélanie Genet (1) , Thierry Chardot (1) , Alain Guillot (2) , Marine Froissard (1)

1 IJPB - Institut Jean-Pierre Bourgin
2 MICALIS - MICrobiologie de l'ALImentation au Service de la Santé

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 ypt7Delta 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. 2015. Published by The Company of Biologists Ltd.

Mots clés: Lipid droplet; Rab GTPase; V-ATPase; Vacuole; Ypt7p

Domaines: Sciences du Vivant [q-bio]

Isabelle Bouchez-Mahiout, Marie Pouteaux, Michel Canonge, Mélanie Genet, Thierry Chardot, et al.. Regulation of lipid droplet dynamics in Saccharomyces cerevisiae depends on the Rab7-like Ypt7p, HOPS complex and V1-ATPase.. Biology Open, 2015, 4 (7), ⟨10.1242/bio.20148615⟩. ⟨hal-01204197⟩