Functions as a ubiquitin E3 ligase and as an ISG15 E3 ligase (PubMed:
16352599). Involved in innate immune defense against viruses by mediating ubiquitination of DDX58 and IFIH1 (PubMed:
17392790, PubMed:
30193849, PubMed:
33849980). Mediates 'Lys-63'-linked polyubiquitination of the DDX58 N-terminal CARD-like region and may play a role in signal transduction that leads to the production of interferons in response to viral infection (PubMed:
17392790, PubMed:
23950712). Mediates 'Lys-63'-linked polyubiquitination of IFIH1 (PubMed:
30193849). Promotes ISGylation of 14-3-3 sigma (SFN), an adapter protein implicated in the regulation of a large spectrum signaling pathway (PubMed:
16352599, PubMed:
17069755). Mediates estrogen action in various target organs (PubMed:
22452784). Mediates the ubiquitination and subsequent proteasomal degradation of ZFHX3 (PubMed:
22452784). Plays a role in promoting the restart of stalled replication forks via interaction with the KHDC3L-OOEP scaffold and subsequent ubiquitination of BLM, resulting in the recruitment and retainment of BLM at DNA replication forks (By similarity).
