E) Quantification of gel-based activity assays where the activity of USP1WT+UAF1 on PCNA-UbWT is compared with PCNA-UbPIM1 shows that PCNA-UbWT is cleaved much faster compared to PCNA-UbPIM1 (n=2, technical replicates (example shown here from 1 of 2 biological replicates)) 