FunctionThe heterodimer acts as a E1 ligase for SUMO1, SUMO2, SUMO3, and probably SUMO4. It mediates ATP-dependent activation of SUMO proteins followed by formation of a thioester bond between a SUMO protein and a conserved active site cysteine residue on UBA2/SAE2.
Tissue specificityExpression level increases during S phase and drops in G2 phase (at protein level).
PathwayProtein modification; protein sumoylation.
Sequence similaritiesBelongs to the ubiquitin-activating E1 family.
Post-translational modificationsPhosphorylated upon DNA damage, probably by ATM or ATR.