Osh6 overexpression extends the lifespan of yeast by increasing vacuole fusion.

Authors: Gebre S; Connor R; Xia Y; Jawed S; Bush JM; Bard M; Elsalloukh H; Tang F

Abstract: In yeast cells, the vacuole divides and fuses in each round of cell cycle. While mutants defective in vacuole fusion are "wild type" for vegetative growth, most have shortened replicative lifespans under caloric restriction (CR) condition, a manipulation that extends lifespan in wild type cells. To explore whether vacuole fusion extends lifespan, we screened for genes that can complement the fusion defect of selected mutants (erg6Delta, a sterol mutant; nyv1Delta, a mutant involved in the vacuolar SNARE complex and vac8Delta, a vacuolar membrane protein mutant). This screen revealed that Osh6, a member of the oxysterol-binding protein family, can complement the vacuole fusion defect of nyv1Delta, but not erg6Delta or vac8Delta, suggesting that Osh6's function in vacuole fusion is partly dependent on membrane ergosterol and Vac8. To measure the effect of OSH6 on lifespan, we replaced the endogenous promoter of OSH6 with a shorter version of the ERG6 promoter to obtain PERG6-OSH6. This mutant construct significantly extended the replicative lifespan in a wild type background and in a nyv1Delta mutant. Interestingly, PERG6-OSH6 cells were more sensitive to drugs that inhibit the activity of the TOR complex 1 (TORC1) than wild type cells. Moreover, a PERG6-OSH6 tor1Delta double mutant demonstrated a greatly shortened lifespan, suggesting a genetic interaction between Osh6 and Tor1. Since active TORC1 stimulates vacuole scission and CR downregulates TORC1, Osh6 may link these two pathways by adjusting vacuolar membrane organization to extend lifespan.

Keywords: Ergosterol/metabolism; Longevity; Membrane Proteins/genetics/metabolism; Phosphatidylinositol 3-Kinases/metabolism; Promoter Regions, Genetic; Protein Structure, Tertiary; Receptors, Steroid/genetics/*metabolism; Saccharomyces cerevisiae/*metabolism; Saccharomyces cerevisiae Proteins/genetics/metabolism; Transcription Factors/metabolism; Up-Regulation; Vacuoles/*metabolism
Journal: Cell cycle (Georgetown, Tex.)
Volume: 11
Issue: 11
Pages: 2176-88
Date: May 25, 2012
PMID: 22622083
Select reference article to upload


Citation:

Gebre S, Connor R, Xia Y, Jawed S, Bush JM, Bard M, Elsalloukh H, Tang F (2012) Osh6 overexpression extends the lifespan of yeast by increasing vacuole fusion. Cell cycle (Georgetown, Tex.) 11: 2176-88.


Study
Update (Admin) | Auto-Update

Comment on This Data Unit