E3 ubiquitin-protein ligase which promotes ubiquitination of YBX1, leading to its degradation by the proteasome (PubMed:18851979). May play a role as a scaffold protein to promote the assembly of the p53/TP53-MDM2 complex, resulting in increase of MDM2-mediated ubiquitination and degradation of p53/TP53; may function as negative regulator of p53/TP53, leading to both apoptosis and cell growth (By similarity). Regulates DNA-replication and the stability of chromosomal common fragile sites (CFSs) in a ZBTB38- and MCM10-dependent manner. Controls ZBTB38 protein stability and abundance via ubiquitination and proteasomal degradation, and ZBTB38 in turn negatively regulates the expression of MCM10 which plays an important role in DNA-replication (PubMed:24726359). (Microbial infection) [Isoform 1]: Restricts ebolavirus replication probably by impairing the vp30-NP interaction, and thus viral transcription. S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E2 ubiquitin-conjugating enzyme]-L-cysteine + N(6)-ubiquitinyl-[acceptor protein]-L-lysine. Protein modification; protein ubiquitination. Interacts with p53/TP53 and RB1 (By similarity). Interacts also with MDM2 and YBX1 (PubMed:17470788). Interacts also with MDM2 and YBX1 (PubMed:18851979). Interacts with NEK6 (PubMed:20873783). Interacts with ZBTB38 (PubMed:24726359). (Microbial infection) [Isoform 1]: Interacts with ebolavirus VP30. Colocalizes with mitotic chromosomes. Colocalizes with NEK6 in the centrosome. Highly expressed in the placenta and testis. Expressed at lower levels in the brain, heart, kidney, liver and lung. Overexpressed in esophageal cancer. Contains a N-terminus DWNN domain, a zinc-finger domain and a C4C4 zinc-binding RING finger domain (PubMed:22130672). The ring finger may indeed be a U-box domain (PubMed:22130672). Phosphorylated by NEK6. Intron retention. Contaminating sequence. Potential poly-A sequence. Intron retention.