The protein encoded by this gene contains two RING-finger motifs and an IBR (in between RING fingers) motif. This protein is an E3 ubiquitin ligase that is localized in Lewy bodies, a characteristic neuronal inclusion in Parkinson's disease (PD) brains. This protein interacts with UBE2L3/UBCH7 and UBE2E2/UBCH8, but not other ubiquitin-conjugating enzymes. This protein binds and ubiquitylates synphilin 1 (SNCAIP) which is an interacting protein of alpha synuclein in neurons and a major component of Lewy bodies. Alternative splicing results in multiple transcript variants encoding the same protein. [provided by RefSeq, Feb 2012].