Proteomic analysis of human T cell‐derived exosomes reveals differential RAS/MAPK signaling

Exosomes are cell‐derived vesicles that have been implicated in the pathogenesis of many inflammatory diseases. More specifically, it has been shown that T cell‐derived exosomes can induce immunological responses; however, little is known about the mechanism and the molecular content of these vesicles. Here, we used a proteomic approach to characterize human T cell‐derived exosomes. We found that specific proteins of the RAS signaling pathway were enriched in exosomes derived from activated T cells, and that these vesicles induced ERK phosphorylation in recipient immune cells. Our findings support a mechanistic role of exosomes in cellular activation, and further studies should consider exosomes as a biomarker for inflammatory diseases. Proteomic analysis of T cell‐derived exosomes reveals unique cargo characterized by enrichment of proteins associated with the RAS/MAPK signaling pathway that once released from the T cells, can induce phosphorylation of ERK in the recipient cells. This study expends our understanding of exosomes vesicular cargo and function.