SUMO1 and hepatocellular carcinoma: To this end, we co-expressed UBL proteins (i.e., MYC-DDK-tagged SUMO-1, HA-tagged SUMO-2, HA-tagged SUMO-3, and MYC-DDK-tagged ISG15) with tagged HBc (i.e., FLAG-tagged or HA-tagged, depending on the used UBL protein) in Huh7 hepatocellular carcinoma cells.