SUMO2 and osteosarcoma: To facilitate the initial experiments for investigating the sumoylation substrates of RanBP2, we expressed His-tagged SUMO2 (His6-SUMO2) in unmodified (wild type or “WT”) and RanBP2 dead E3 (“RanBP2-dE3”) human osteosarcoma (U2OS) cell lines, which we generated previously by CRISPR/Cas9 [22].