Crebbp (Cbp) is sumoylated at lysine-999, lysine-1034, and lysine-1057 with Sumo1 (Kuo et al. 2005, Ryan et al. 2010, Shih et al. 2007). Sumoylation recruits Daxx and Hdac2 to repress transcription.
SUMO transferase activity of Sumo1:C93-Ube2i [nucleoplasm]