RING finger protein 152(RNF152)is a novel RING finger protein and has not been well characterized.We report here that RNF152 is a canonical RING finger protein and has E3 ligase activity.It is polyubiqitinated partly through Lys-48-linked ubiquitin chains in vivo and this phenomenon is dependent on its RING finger domain and transmembrane domain.RNF152 is localized in lysosomes and co-localized with LAMP3,a lysosome marker.Moreover,over-expression of RNF152 in Hela cells induces apoptosis.These results suggest that RNF152is a lysosome localized E3 ligase with pro-apoptotic activities.It is the first E3 ligase identified so far that is involved in lysosome-related apoptosis.