Systems-wide analysis of ubiquitylation dynamics reveals a key role for PAF15 ubiquitylation in DNA-damage bypass

Nat Cell Biol. 2012 Oct;14(10):1089-98. doi: 10.1038/ncb2579. Epub 2012 Sep 23.


Protein ubiquitylation has emerged as a key regulatory mechanism in DNA-damage signalling and repair pathways. We report a proteome-wide, site-specific survey of ubiquitylation changes after ultraviolet irradiation, identifying numerous upregulated and downregulated ubiquitylation sites on known components of DNA-damage signalling, as well as on proteins not previously implicated in this process. Our results uncover a critical role for PCNA-associated factor PAF15 (p15(PAF)/KIAA0101) ubiquitylation during DNA replication. During unperturbed S phase, chromatin-associated PAF15 is modified by double mono-ubiquitylation of Lys 15 and 24 templated through PCNA binding. Replication blocks trigger rapid, proteasome-dependent removal of Lys 15/24-ubiquitylated PAF15 from PCNA, facilitating bypass of replication-fork-blocking lesions by allowing recruitment of translesion DNA synthesis polymerase polη to mono-ubiquitylated PCNA at stalled replisomes. Our findings demonstrate widespread involvement of ubiquitin signalling in genotoxic-stress responses and identify a critical function for dynamic PAF15 ubiquitylation in safeguarding genome integrity when DNA replication is challenged.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carrier Proteins / metabolism*
  • Cell Line
  • DNA Damage / physiology*
  • DNA Repair / physiology*
  • DNA Replication / physiology
  • DNA-Binding Proteins
  • DNA-Directed DNA Polymerase / metabolism
  • Humans
  • Lysine / metabolism
  • Proteasome Endopeptidase Complex / metabolism
  • S Phase / physiology
  • Signal Transduction / physiology
  • Ubiquitination*
  • Ultraviolet Rays / adverse effects*


  • Carrier Proteins
  • DNA-Binding Proteins
  • PCLAF protein, human
  • DNA-Directed DNA Polymerase
  • Rad30 protein
  • Proteasome Endopeptidase Complex
  • Lysine