Functional difference of acquired mutations in driving the SUMOylation of PML-RARA proteins in HeLa cells. Immunoblotting analyses for (A) Flag-tagged PR-L-WT and its mutants cotransfected with HA-tagged SUMO-2 or its negative control in HeLa cells; (B) Flag-tagged PR-L-WT and its mutants cotransfected with HA-tagged SUMO-2, respectively, followed by treatment with or without As₂O₃ (1 μM, 16 hours) in HeLa cells. Top row, protein levels in the soluble fraction isolated from whole-cell lysates were detected by anti-Flag and anti-Tubulin antibodies. Middle and bottom rows, protein levels in detergent-insoluble pellets from whole-cell lysates were detected by anti-Flag and anti-HA primary antibodies, respectively.