Surface protein profiling of prostate derived extracellular vesicles

Extracellular vesicles (EVs) are mediators of intercellular communication and a promising class of biomarkers. Surface proteins of EV play decisive roles in establishing a connection with recipient cells, and they are putative targets in diagnostic assays. Analysis of the surface proteins can thus both illuminate the biological functions of EVs and help identify potential biomarkers. The surface proteins of intact seminal fluid ssmall EV (SF-sEVs and PC3) sEVs were labeled using sulfo-NHS-SS-biotin, a membrane-impermeable reagent reacting with primary amines. The fractions obtained from the purification process were: (i) protein in total sEV lysate (Total); (ii) proteins isolated from sEV surfaces (Surface), and (iii) supernatant proteins left after isolation of surface proteins (Total minus Surface). Proteins from each fraction were digested by trypsin and analyzed by HRMS. A total PC3 cell lysate was prepared andanalyzed as a control.