Figure 6.

Proposed model of DPC ubiquitination and repair. Following recognition of a DPC lesion by NER machinery, DPCs are modified with K48- linked polyubiquitin chains. K48-polyubiquitination of DPC triggers proteasomal recruitment to and degradation of the crosslinked protein, eliminating steric hindrance by the DPC and allowing access to the DNA backbone by NER machinery. In the absence of NER machinery, DPCs are K63-polyubiquitinated. HR machinery are recruited to K63-polyubiquitinated DPCs and initiate a homologous donor search resulting in nucleolytic DPC repair by HR.