CRL4(Cdt2) E3 ubiquitin ligase monoubiquitinates PCNA to promote translesion DNA synthesis.
Monoubiquitination of proliferating cell nuclear antigen (PCNA) is a critical posttranslational modification essential for DNA repair by translesion DNA synthesis (TLS). The Rad18 E3 ubiquitin ligase cooperates with the E2 Rad6 to monoubiquitinate PCNA in response to DNA damage. How PCNA is monoubiquitinated in unperturbed cells and whether this plays a role in the repair of DNA associated with replication is not known. We show that the CRL4(Cdt2) E3 ubiquitin ligase complex promotes PCNA monoubiqutination in proliferating cells in the absence of external DNA damage independent of Rad18. PCNA monoubiquitination via CRL4(Cdt2) is constitutively antagonized by the action of the ubiquitin-specific protease 1 (USP1). In vitro, CRL4(Cdt2) monoubiquitinates PCNA at Lys164, the same residue that is monoubiquitinated by Rad18. Significantly, CRL4(Cdt2) is required for TLS in nondamaged cells via a mechanism that is dependent on PCNA monoubiquitination. We propose that CRL4(Cdt2) regulates PCNA-dependent TLS associated with stresses accompanying DNA replication.
Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908, USA.
Kenta
K
Terai
Tarek
T
Abbas
Amir A
AA
Jazaeri
Anindya
A
Dutta
D002460:Cell Line; D004249:DNA Damage; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000502:physiology; D006367:HeLa Cells; D006801:Humans; D009687:Nuclear Proteins / Q000378:metabolism / Q000502:physiology*; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism / Q000502:physiology*; D054875:Ubiquitination
D004268:DNA-Binding Proteins; C429530:DTL protein, human; D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; C485954:RAD18 protein, human; D044767:Ubiquitin-Protein Ligases