(A) Summary of HMCES recovery upon TAP-MS analyses performed with 293T cells stably expressing SFB-PCNA. Cells were treated with CPT: camptothecin (1 μg/ml for 6 h); HU: hydroxyurea (2 mM for 16 h), UV: ultraviolet light irradiation (10 mJ/cm2 harvested after 6 h post-irradiation) or Thymidine (100 mM for 6 h). Recovered peptide-spectrum matches (PSMs) for PCNA and HMCES are indicated for each condition. 