Modification of PCNA by ISG15 plays a crucial role in termination of error-prone translesion DNA synthesis

Mol Cell. 2014 May 22;54(4):626-38. doi: 10.1016/j.molcel.2014.03.031. Epub 2014 Apr 24.

Abstract

In response to DNA damage, PCNA is mono-ubiquitinated and triggers translesion DNA synthesis (TLS) by recruiting polymerase-η. However, it remained unknown how error-prone TLS is turned off after DNA lesion bypass to prevent mutagenesis. Here we showed that ISG15 modification (ISGylation) of PCNA plays a key role in TLS termination. Upon UV irradiation, EFP, an ISG15 E3 ligase, bound to mono-ubiquitinated PCNA and promoted its ISGylation. ISGylated PCNA then tethered USP10 for deubiquitination and in turn the release of polymerase-η from PCNA. Eventually, PCNA was deISGylated by UBP43 for reloading of replicative DNA polymerases and resuming normal DNA replication. However, ISGylation-defective Lys-to-Arg mutations in PCNA or knockdown of any of ISG15, EFP, or USP10 led to persistent recruitment of mono-ubiquitinated PCNA and polymerase-η to nuclear foci, causing an increase in mutation frequency. These findings establish a crucial role of PCNA ISGylation in termination of error-prone TLS for preventing excessive mutagenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arginine / metabolism
  • Binding Sites / genetics
  • Cytokines / genetics
  • Cytokines / metabolism*
  • DNA Damage*
  • DNA Polymerase II / metabolism
  • DNA Repair
  • DNA Replication*
  • Gene Expression Regulation
  • Gene Knockdown Techniques
  • HeLa Cells
  • Humans
  • Lysine / metabolism
  • Mutagenesis
  • Mutation Rate
  • Proliferating Cell Nuclear Antigen / genetics*
  • Proliferating Cell Nuclear Antigen / metabolism*
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Tripartite Motif Proteins
  • Ubiquitin Thiolesterase / genetics
  • Ubiquitin Thiolesterase / metabolism
  • Ubiquitin-Protein Ligases / genetics
  • Ubiquitin-Protein Ligases / metabolism
  • Ubiquitination
  • Ubiquitins / genetics
  • Ubiquitins / metabolism*

Substances

  • Cytokines
  • Proliferating Cell Nuclear Antigen
  • Transcription Factors
  • Tripartite Motif Proteins
  • USP10 protein, human
  • Ubiquitins
  • ISG15 protein, human
  • Arginine
  • TRIM25 protein, human
  • Ubiquitin-Protein Ligases
  • DNA Polymerase II
  • Ubiquitin Thiolesterase
  • Lysine