SUMO-conjugating enzyme UBC9 (UBE2I)

Accepts the ubiquitin-like proteins SUMO1, SUMO2, SUMO3, SUMO4 and SUMO1P1/SUMO5 from the UBLE1A-UBLE1B E1 complex and catalyzes their covalent attachment to other proteins with the Support of an E3 ligase like RANBP2, CBX4 and ZNF451.

Can catalyze the formation of poly-SUMO chains.

Necessary for sumoylation of FOXL2 and KAT5. Essential for nuclear architecture and chromosome segregation.