Components of the NEDD8 conjugation machinery are enriched in HALO-NEDP1 pulldowns from NEDP1 KO lysates. Neddylated proteins from HEK293 KO cells were enriched by HALO-NEDP1 CA pulldown, as in (B) but not by the NEDD8 nonbinder mutant, HALO-NEDP1 DAGC (D29W A98K G99K C163A). The NEDD8 E1s, UBA3 and ULA1, are modified in NEDP1 KO cells, as well as E2 UBE2M, and co-E3s DCNL1 and DCNL2. Cul2 and Cul3 are hyper-neddylated in NEDP1 KO cells. CSN components, CSN5 and CSN8, also co-precipitate in HALO-NEDP1 CA pulldowns. 