Complex N ‐linked glycans serve as a determinant for exosome/microvesicle cargo recruitment (788.5)

Exosomes, also known as microvesicles (EMVs), are nano‐sized membrane particles secreted from nearly all mammalian cell types. These nanoparticles play critical roles in many physiological processes including cell‐cell signaling, immune activation and suppression, and are associated with disease states such as tumor progression. The biological functions of EMVs are highly dependent on their protein cargo, which can dictate pathogenicity. While some mechanisms have been proposed for the regulation of EMV cargo selection, little attention has been paid to N ‐linked glycosylation as a potential sorting signal. Previous work from our laboratory found a conserved glycan signature for EMVs, which differed from the overall cellular membranes, suggesting a potential role for glycosylation in EMV biogenesis. In this study, we explore further the role of glycosylation in EMV cargo selection. We identify specific glycosylated targets and associated proteins and demonstrate alteration of their recruitment as a function of their glycosylation status upon pharmacological manipulation. Further, we show that genetic manipulation of the glycosylation levels of a MV cargo glycoprotein EWI‐2 directly impacts its recruitment as a function of N ‐linked glycan sites. Taken together, our data provided strong evidence that N ‐linked glycosylation directs glycoprotein sorting into EMVs and serves as a determinant of EMV cargo selection. Grant Funding Source : Supported by Mizutani Foundation for Glycoscience