Characterization of intracellular interactome CD81 and EWI-2 in human T-Limphocytes

In this work, we made a deeper insight into the proximal cytosolic interactome of EWI-2 and CD81 by analyzing the interactions of these proteins in human exosomes, which are known to be enriched in TEM proteins. 27 pull-down experiments from 6 different donors were performed using the biotinylated cytosolic C-terminal domains from EWI-2 and CD81 as baits, followed by high-throughput mass spectrometry identification of the interacting partners. The number of identified peptides per protein in each interactome was assessed and compared to a control pull-down experiment performed with beads without bait. More than 270 specific interactions were characterized from a total of 2880 identified proteins. These interacting partners were differentially clustered revealing strong relationships between those baits and confirming previous characterizations. New differential clusters of proteins were also detected, such as CD proteins with CD81, GTP-binding proteins with EWI-2, or both baits with Ras-related proteins.