Proteomic Characterization of EVs in Non-pathogenic Yeast Cells

Most research on extracellular vesicles (EVs) from non-pathogenic fungi has been conducted in S. cerevisiae, taking advantage of the tools available for this model organism; but a few studies on EVs from yeasts of biotechnological interest are also available. Proteomic analyses in EVs from different yeast species and under different culture conditions are consistent in the identification of proteins related to glycolysis and cell wall biogenesis. Consequently, cell wall metabolism and biosynthesis appear as major functions of EVs. Additional functions have been proposed attending to the known biological activities identified on EVs proteomes, including interspecific antagonism, protection against antimicrobial agents, or clearance of aggregates of misfolded proteins (e.g. prion-like proteins). However, caution should be taken since some of these proteins might play a different role in the intracellular space or EVs (including some well known moonlighting proteins). It is also possible that many proteins appear in EVs as an indirect consequence of cellular metabolism and protein traffic, not related to a specific role in the extracellular space. These considerations become especially relevant in the context of the increasing detection power of proteomic technologies, leading in some cases to the identification of thousands of different proteins in the EVs proteome. Mutations in different secretory pathways have been related to differences in protein cargo of EVs, but no mutation has been found completely abolishing the production of EVs. Further work on the composition and biogenesis of EVs is required to better understand their biological significance.