Intercellular transfer of proteins and mitochondria - the contribution of proteomics

One of the mechanisms of intercellular communication is the transfer of proteins and organelles among cells. This has been observed in diverse phylogenetic groups, and can be mediated by extracellular vesicles, like exosomes or exophores, tunneling nanotubes, pores like plasmodesmata or processes like trogocytosis. The vast majority of studies in this field have used confocal microscopy and flow cytometry to detect proteins from donor cells in recipient cells. Proteomics has not been widely used, despite the fact that efficient tools are available for the labeling, enrichment and unbiased large-scale identification of the transferred proteins. Among these tools are trans-SILAC, affinity capture-MS/MS, BONCAT, TransitID and the use of cells from different species. In this review we describe illustrative examples of the intercellular transfer of proteins and mitochondria indicating the experimental methodologies used, both proteomics and non-proteomics, and emphasizing the capabilities of the mass spectrometry-based strategies.