NEDD8 trimers co-immunoprecipitate with endogenous PARP-1 in NEDP1 KO cells. Lysates were prepared from U2OS NEDP1 KO cells and immunoprecipitation was performed with PARP-1-Trap or GFP-Trap as a negative control. Bound proteins were resolved by SDS-PAGE and processed for Western blot analysis with the indicated antibodies. 