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Nucleic Acids Res. 2014 Apr;42(6):3692-706. doi: 10.1093/nar/gkt1400. Epub 2014 Jan 14.

PIP degron proteins, substrates of CRL4Cdt2, and not PIP boxes, interfere with DNA polymerase η and κ focus formation on UV damage.

Author information

1
Genome Surveillance and Stability Laboratory, Department of Molecular Bases of Human Diseases, CNRS-UPR1142, Institute of Human Genetics, 141, rue de la cardonille, 34396 Cedex 5, Montpellier, France and Replication and Genome Dynamics Laboratory, Department of Genome Dynamics, CNRS-UPR1142, Institute of Human Genetics, 141, rue de la cardonille, 34396 Cedex 5, Montpellier, France.

Abstract

Proliferating cell nuclear antigen (PCNA) is a well-known scaffold for many DNA replication and repair proteins, but how the switch between partners is regulated is currently unclear. Interaction with PCNA occurs via a domain known as a PCNA-Interacting Protein motif (PIP box). More recently, an additional specialized PIP box has been described, the « PIP degron », that targets PCNA-interacting proteins for proteasomal degradation via the E3 ubiquitin ligase CRL4(Cdt2). Here we provide evidence that CRL4(Cdt2)-dependent degradation of PIP degron proteins plays a role in the switch of PCNA partners during the DNA damage response by facilitating accumulation of translesion synthesis DNA polymerases into nuclear foci. We show that expression of a nondegradable PIP degron (Cdt1) impairs both Pol η and Pol κ focus formation on ultraviolet irradiation and reduces cell viability, while canonical PIP box-containing proteins have no effect. Furthermore, we identify PIP degron-containing peptides from several substrates of CRL4(Cdt2) as efficient inhibitors of Pol η foci formation. By site-directed mutagenesis we show that inhibition depends on a conserved threonine residue that confers high affinity for PCNA-binding. Altogether these findings reveal an important regulative role for the CRL4(Cdt2) pathway in the switch of PCNA partners on DNA damage.

PMID:
24423875
PMCID:
PMC3973308
DOI:
10.1093/nar/gkt1400
[Indexed for MEDLINE]
Free PMC Article

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