Anti-UBE1L2/MOP-4

Uba6/UBE1L2/MOP-4 is an ubiquitin-specific E1 type enzyme, homolog of the ubiquitin-activating enzyme, Uba1, which activates two ubiquitin-like proteins (UBLs), ubiquitin and FAT10. Some recent experiments suggest a testis-specific function of UBE1L2. UBE1L2 forms a thioester with FAT10 and this reaction requires the active-site cysteine of UBE1L2 and the C-terminal diglycine motif of FAT10. It can transfer ubiquitin to Ubc5 and Ubc13, suggesting its specialized role in ubiquitination reactions. Protein function: Activates ubiquitin by first adenylating its C-terminal glycine residue with ATP, and thereafter linking this residue to the side chain of a cysteine residue in E1, yielding a ubiquitin- E1 thioester and free AMP. Specific for ubiquitin, does not activate ubiquitin-like peptides. Differs from UBE1 in its specificity for substrate E2 charging. Does not charge cell cycle E2s, such as CDC34. Essential for embryonic development. Required for UBD/FAT10 conjugation. Isoform 2 may play a key role in ubiquitin system and may influence spermatogenesis and male fertility. [The UniProt Consortium]