SUMO E1 captured during thioester bond formation

E3-E2 ligase complexes with the RanGAP1 substrate (pink), the E2 Ubc9 (blue), SUMO (orange or brown), and the E3s RanBP2 (left) or ZNF451 (right)

E3-E2-SUMO-PCNA complex captured in action

Recognition of SUMO-PCNA by the the C-terminal domain of the Srs2 helicase