BLM is SUMOylated at lysine-317, lysine-331, lysine-344, and lysine-347 with SUMO2,3 (Eladad et al. 2005, Zhu et al. 2008, Ouyang et al. 2009, Ouyang et al. 2013, Hendriks et al. 2014). SUMOylation causes BLM to localize to PML bodies (Eladad et al. 2005). SUMOylated BLM recruits RAD51, which directly binds SUMO, and facilitates the substitution of RAD51 for RPA at stalled replication forks (Ouyang et al. 2009, 2013).