UBE2I and neoplasm: In Epstein–Barr virus (EBV), LMP1 regulates SUMOylation through two primary mechanisms: First, its CTAR3 domain directly binds to SUMO ligase Ubc9, thereby promoting SUMOylation of intracellular proteins and enhancing tumor cell migration; Second, it activates the NF-κB pathway through its CTAR1/CTAR2 domains, thereby upregulating SUMO and related regulatory proteins (Bentz et al., 2011; Salahuddin et al., 2019).