Cell to cell signaling via exosomes (transport of genetic material between cells via exosomes

RNA-binding proteins (RBPs) present in exosomes derived from HTB177 cells (NCI-H460 [H460] (ATCC: HTB-177) were identified as described below. For more detailed description please see Statello L, Maugeri M, Garre E, Nawaz M, Wahlgren J, Papadimitriou A, et al. (2018) (doi: 10.1371/journal.pone.0195969. eCollection 2018). List of the identified proteins can be found in the section 'Data collection' as well as on the journal's website (journals.plos.org/plosone/article?id=10.1371/journal.pone.0195969#sec025).

Identification of RNA binding proteins in exosomes and their parent cells: To detect and isolate the RBPs in cells and exosomes, the biotinylated esRNAs, cellular miRNAs, and cellular mRNAs were attached to streptavidin-coated paramagnetic Dynabeads M-280 and were incubated with native protein extracts of exosomes in separate RNA species assays (total exosomal-protein extract + esRNA;, total exosomal-protein extract + cell-mRNA;, total exosomal-protein extract + cell-miRNA).

The protein-RNA complexes were eluted from the beads. The RBPs bound to the different RNAs were then loaded onto an SDS-PAGE gel and target bands were excised, trypsinised and analyzed using LC-MS/MS. Samples without RNA were processed in parallel and were used as negative controls to identify proteins that bound non-specifically to the beads.