Identification of UFD1 and NPLOC4 as the p97 cofactors involved in arsenic-induced PML degradation. U2OS PML^−/− + YFP-PML cells were treated with NT or with siRNAs to the indicated p97 cofactors and exposed to arsenic for the times indicated. (A) Cell lysates were analyzed by Western blotting with antibodies to PML and Lamin A/C. (B) Western blotting for the indicated p97 cofactors in whole-cell extracts from cells treated with the indicated siRNAs. Molecular weight markers are indicated in kD. Source data are available for this figure: SourceData FS3.