Format

Send to

Choose Destination
See comment in PubMed Commons below
Int J Biol Sci. 2008;4(6):352-61. Epub 2008 Oct 4.

A PP1-binding motif present in BRCA1 plays a role in its DNA repair function.

Author information

  • 1Department of Obstetrics, Gynecology and Reproductive Sciences, School of Medicine, University of Pittsburgh, Magee-Womens Research Institute, Pittsburgh, PA15213, USA.

Abstract

Protein phosphatase 1alpha (PP1alpha) regulates phosphorylation of BRCA1, which contains a PP1-binding motif (898)KVTF(901). Mutation of this motif greatly reduces the interaction between BRCA1 and PP1alpha. Here we show that mutation of the PP1-binding motif abolishes the ability of BRCA1 to enhance survival of Brca1-deficient mouse mammary tumor cells after DNA damage. The Rad51 focus formation and comet assays revealed that the DNA repair function of BRCA1 was impaired when the PP1-binding motif was mutated. Analysis of subnuclear localization of GFP-tagged BRCA1 demonstrated that mutation of the PP1-binding motif affected BRCA1 redistribution in response to DNA damage. BRCA1 is required for the formation of Rad51 subnuclear foci after DNA damage. Mutation of the PP1-binding motif in BRCA1 also affected recruitment of Rad51 to sites of DNA damage. Consistent with these findings, knockdown of PP1alpha in BRCA1-proficient cells by small interfering RNA also significantly reduced Rad51 focus formation induced by DNA damage. Further analysis indicated that mutation of the PP1-binding motif compromised BRCA1 activities in homologous recombination. Altogether, our data implicate that interaction with PP1alpha is important for BRCA1 function in DNA repair.

KEYWORDS:

BRCA1; DNA repair; protein phosphatase 1

PMID:
18953404
PMCID:
PMC2567813
[PubMed - indexed for MEDLINE]
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Ivyspring International Publisher Icon for PubMed Central
    Loading ...
    Write to the Help Desk