NEDD8 trimers bind to GFP-PARP-1. NEDP1 U2OS KO cells were transfected with GFP or with GFP-PARP-1 and 24 hours later cell lysates were collected. Immunoprecipitation was then performed with GFP-Trap, and bound proteins were resolved by SDS-PAGE and processed for Western blot analysis with the indicated antibodies. GFP-PARP-1 but not GFP alone can co-immunoprecipitate NEDD8 trimers from NEDP1 KO cells. 