USP7 and VCPFAF1 define the SUMO/Ubiquitin landscape at the DNA replication fork

Summary The AAA+ ATPase VCP regulates the extraction of SUMO and ubiquitin-modified DNA replication factors from chromatin. We have previously described that active DNA synthesis is associated with a SUMO-high/ubiquitin-low environment governed by the deubiquitylase USP7. Here, we unveil a functional cooperation between USP7 and VCP in DNA replication, which is conserved from Caenorhabditis elegans to mammals. The role of VCP in chromatin is defined by its cofactor FAF1, which facilitates the extraction of SUMOylated and ubiquitylated proteins that accumulate after the block of DNA replication in the absence of USP7. The inactivation of USP7 and FAF1 is synthetically lethal both in C. elegans and mammalian cells. In addition, USP7 and VCP inhibitors display synergistic toxicity supporting a functional link between deubiquitylation and extraction of chromatin-bound proteins. Our results suggest that USP7 and VCPFAF1 facilitate DNA replication by controlling the balance of SUMO/Ubiquitin-modified DNA replication factors on chromatin.
Graphical abstract
Highlights • VCP and USP7 control the SUMO/ubiquitin landscape during DNA replication • VCP is recruited by FAF1 to chromatin-associated SUMO/ubiquitylated proteins • FAF1 recognizes both SUMO and ubiquitin on target proteins • The control of DNA replication by VCPFAF1 and USP7 is evolutionarily conserved
Chromatin at DNA replication forks is SUMO-rich and ubiquitin-poor. Franz et al. report that FAF1 is a dual reader of SUMO and ubiquitin targeting VCP to extract DNA replication factors from chromatin in C. elegans and human cells. Together with USP7, VCPFAF1 controls the SUMO/ubiquitin landscape during replication.