Mouse Ubiquitin-like Modifier-activating Enzyme 1, UBA1 ELI

Catalyzes the first step in ubiquitin conjugation to mark cellular proteins for degradation through the ubiquitin-proteasome system (PubMed:1511901). 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.

Essential for the formation of radiation-induced foci, timely DNA repair and for response to replication stress.

Promotes the recruitment of TP53BP1 and BRCA1 at DNA damage sites.