Polyubiquitinated PCNA Recruits the ZRANB3 Translocase to Maintain Genomic Integrity after Replication Stress

Abstract

Summary Completion of DNA replication after replication stress depends on PCNA, which undergoes mono-ubiquitination to stimulate direct bypass of DNA lesions by specialized DNA polymerases or is poly-ubiquitinated to promote recombination dependent DNA synthesis across DNA lesions by template switching mechanisms. Here we report that the ZRANB3 translocase, a SNF2 family member related to the SIOD disorder SMARCAL1 protein, is recruited by poly-ubiquitinated PCNA to promote fork restart following replication arrest. ZRANB3 depletion in mammalian cells results in an increased frequency of sister chromatid exchange and DNA damage sensitivity after treatment with agents that cause replication stress. Using in vitro biochemical assays, we show that recombinant ZRANB3 remodels DNA structures mimicking stalled replication forks and disassembles recombination intermediates. We therefore propose that ZRANB3 maintains genomic stability at stalled or collapsed replication forks by facilitating fork restart and limiting inappropriate recombination that could occur during template switching events.

DNA damage tolerance pathway involving DNA polymerase ι and the tumor suppressor p53 regulates DNA replication fork progression

“…Intriguingly, it has previously been speculated that p53 is required for efficient, UV-induced PCNA monoubiquitination (39,61). The p53 effect on replication-associated recombination was partially epistatic [residual effect in cells with p53(H115N)] with the Rad5 functional homolog HLTF, which, in conjunction with UBC13/UEV1, polyubiquitinates PCNA (42), and with the translocase ZRANB3, which binds polyubiquitinated PCNA and stabilizes replication forks (45). Intriguingly, HLTF and ZRANB3 may also support a RAD51-independent mechanism of lesion bypass.…”

“…A major function of HLTF appears to be the promotion of fork reversal upon replication block (43,64,65). ZRANB3, a SWI/ SNF catalytic subunit (SNF2) DNA translocase like HLTF, has been proposed to cooperate with HLTF in the remodeling of the blocked fork, additionally contributing a structure-specific endonuclease for the fork remodeling (45,66,67). PCNA ubiquitination has been described to mediate a switch of POLs and to induce TLS (38).…”

The ADP-ribosyltransferase PARP10/ARTD10 Interacts with Proliferating Cell Nuclear Antigen (PCNA) and Is Required for DNA Damage Tolerance

“…Interestingly, PARP10 contains two tandem UIM domains, found to bind to K63-linked multi-ubiquitin chains (35). PCNA is itself subjected to K63-linked multiubiquitination, and was recently shown to recruit the ZRANB3 helicase (55). This raises the possibility that PARP10 might also interact with multi-ubiquitinated PCNA.…”

PCNA-Ub polyubiquitination inhibits cell proliferation and induces cell-cycle checkpoints

“…Secondly, despite a well-demonstrated sequential PCNA ubiquitination model in budding yeast and intensively studied PCNA monoubiquitination in mammalian cells, it remains inconclusive whether PCNA is polyubiquitinated in mammals upon DNA damage, 13,62 although a mammalian ZARANB3/AH2 has been identified to bind PCNA and K63-linked Ub chain through its 2 PCNA-binding domains and a specialized NPL4 zinc fingerbinging domain, respectively. 63 Thirdly, based on the Ub structure, the K63 residue is adjacent to the Met1 residue and hence the linear Ub chain topologically resembles K63-linked polyUb chain and differs from K48-linked polyUb chain, suggesting that PCNA linear polyubiquitination could functionally resemble its K63-linked polyubiquitination. However, one has to be aware that for PCNA-K164 ubiquitination, the C-terminal Gly of Ub is linked to K164, making its N-terminus and surface Lys available, whereas in the PCNA-Ub fusion, its C-terminal Gly is absolutely required while its Nterminus is unavailable.…”