A. HEK293 or U2OS/MycBioID-FAM111A cell lines were induced with doxycycline for 24 h. Total protein from 105 cells was resolved by SDS-PAGE, and probed in western blots for both endogenous FAM111A (71 kDa) and MycBioID-FAM111A (110 kDa) as well as full length and cleaved PARP (116 and 89 kDa, respectively). The Tubulin western blot is a sample loading control. 