Roles of PCNA-binding and ubiquitin-binding domains in human DNA polymerase η in translesion DNA synthesis

Narottam Acharya, Jung Hoon Yoon, Himabindu Gali, Ildiko Unk, Lajos Haracska, Robert Johnson, Jerard Hurwitz, Louise Prakash, Satya Prakash

Research output: Contribution to journalArticlepeer-review

102 Scopus citations


Treatment of yeast and human cells with DNA-damaging agents elicits Rad6-Rad18-mediated monoubiquitination of proliferating cell nuclear antigen (PCNA) at its Lys-164 residue [ubiquitin (Ub)-PCNA], and this PCNA modification is indispensable for promoting the access of translesion synthesis (TLS) polymerases (Pols) to PCNA. However, the means by which K164-linked Ub modulates the proficiency of TLS Pols to bind PCNA and take over synthesis from the replicative Pol has remained unclear. One model that has gained considerable credence is that the TLS Pols bind PCNA at 2 sites, to the interdomain connector loop via their PCNA-interacting protein (PIP) domain and to the K164-linked Ub moiety via their Ub-binding domain (UBD). Specifically, this model postulates that the UBD-mediated binding of TLS Pols to the Ub moiety on PCNA is necessary for TLS. To test the validity of this model, we examine the contributions that the PIP and Ub-binding zinc finger (UBZ) domains of human Polη make to its functional interaction with PCNA, its colocalization with PCNA in replication foci, and its role in TLS in vivo. We conclude from these studies that the binding to PCNA via its PIP domain is a prerequisite for Polη's ability to function in TLS in human cells and that the direct binding of the Ub moiety on PCNA via its UBZ domain is not required. We discuss the possible role of the Ub moiety on PCNA in TLS.

Original languageEnglish (US)
Pages (from-to)17724-17729
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number46
StatePublished - Nov 18 2008


  • Exchange
  • PCNA ubiquitination
  • PIP domain
  • UBZ domain

ASJC Scopus subject areas

  • General


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