Intracellular Triacylglycerol Promotes Longevity during Chronological Aging of Yeast

Intracellular triacylglycerol (TAG) is a ubiquitous energy storing lipid also involved in lipid homeostasis and signaling. However, very little is known about TAG's function in other cellular processes. Here we show a novel anti-senescence function of TAG in the budding yeast Saccharomyces cerevisiae. Yeast strains derived from natural and laboratory environments exhibited a correlation in stationary phase between higher levels of TAG and increased chronological lifespan. Upregulation of stationary phase TAG abundance through the deletion of TAG lipases prolonged chronological lifespan of laboratory strains, while diminishing TAG biosynthesis shortened lifespan without significantly affecting vegetative growth. The observed increase in lifespan was independent of other known stress response factors involved in chronological aging. Because both lifespan regulation and TAG metabolism are conserved through evolution, the pro-longevity function of TAG may extend to other organisms as well.