May function as a transcriptional repressor. May also function as a ubiquitin ligase mediating ubiquitination of chromatin-associated TP53. Functions in cell survival and proliferation through control of the cell cycle. Functions in the p53 and pRB tumor suppressor pathways and regulates the cyclin CCNA2 transcription.; Identified as a cellular target of the adenoviral oncoprotein E1A, it is required for both transcriptional activation and repression of viral genes.
