Proteostasis is partly dependent on quality control mechanisms to detect unfolded proteins and either refold or degrade them. These pathways clear toxic unfolded protein aggregates that appear during aging or under stress for cell survival. However, recent studies suggest that survival of cell populations also rely on extracellular vesicles (EVs) shared under proteotoxic stress. EVs are nanosized lipid membrane-bound carriers of complex biomolecules thought to mediate intercellular communication underlying diverse physiology in humans and across phyla. However, their contributions to proteostasis remain unclear. 
	Given that the molecular machinery underlying EV biogenesis is conserved in all eukaryotes, I reasoned that Saccharomyces cerevisiae (baker’s yeast) may serve as a simple model to better understand how EVs may circumvent proteotoxicity in molecular detail. I first optimized methods for isolating and characterizing EVs from yeast by tracking GFP-tagged Bro1, the yeast homolog of ALIX, an established EV biomarker in humans. Using fluorescence microscopy, I show that yeast cells readily share EVs during mild heat stress, and characterize morphology, size and protein content using, scanning probe microscopy, dynamic light scattering and mass spectrometry. Adding these isolated EVs to naïve (unstressed) cells protects them from lethal heat stress. This effect is lost when EVs were collected during osmotic stress or from cells lacking HSC82 or SSA2, genes encoding protein chaperones that are abundant in EVs. I conclude that yeast share EVs containing protein chaperones during heat stress to protect against proteotoxicity for survival, and speculate that EVs may help coordinate proteostasis between cells in all organisms.