The protein encoded by this gene is an E3 ubiquitin-protein ligase that polyubiquitinates some proteins, tagging them for degradation. The encoded protein upregulates p53 in some cancer cells and may inhibit myelopoiesis. Several transcript variants encoding different isoforms have been found for this gene, although the full-length nature of some of them have not been determined yet. [provided by RefSeq, Nov 2015].