The complex of RAD18, an E3 ubiquitin ligase, and UBE2B (RAD6), an E2 ubiquitin-conjugating enzyme, binds the replication complex consisting of PCNA, DNA polymerase complex delta (POLD) or DNA polymerase complex epsilon (POLE), RPA and RFC on damaged dsDNA. RAD18 simultaneously interacts with PCNA, RPA and DNA (Hoege et al. 2002, Notenboom et al. 2007, Davies et al. 2008). The ubiquitin ligase complex RBX1:CUL4:DDB1:DTL can also bind PCNA (Terai et al. 2010).