PR-619 is widely used as a reversible inhibitor of deubiquitinating enzymes (DUBs), making it a valuable tool in studying the ubiquitin-proteasome system. It is commonly applied in cellular and molecular research to investigate protein degradation pathways, particularly in cancer and neurodegenerative disease models. PR-619 induces accumulation of ubiquitinated proteins, helping researchers assess the role of DUBs in cell cycle regulation, apoptosis, and DNA damage response. It is also used in screening assays to identify DUB activity and evaluate potential therapeutic targets. Due to its cell permeability, it is effective in both in vitro and cell-based studies, supporting drug discovery and mechanistic studies in signal transduction pathways.