The K898E germline variant in the PP1-binding motif of BRCA1 causes defects in DNA Repair
Journal
Scientific Reports
Journal Volume
4
Pages
5812
Date Issued
2014
Author(s)
Abstract
BRCA1 is a phosphoprotein involved in many biological processes, including transcription, ubiquitination, checkpoint control, homologous recombination, and DNA repair. We have demonstrated that protein phosphatase 1?± (PP1?±) interacts with BRCA1 via a PP1-binding motif 898 KVTF 901, and can dephosphorylate multiple serine residues phosphorylated by checkpoint kinases. A K898E germline missense variant in the PP1-binding motif of BRCA1 has been found in an Ashkenazi patient and a non-Ashkenazi Argentinean patient with breast and ovarian cancer, but its clinical significance is still unknown. Here we report that the lysine residue in the PP1-binding motif of BRCA1 is highly conserved across many mammalian species. The K898E mutation interferes with the interaction between BRCA1 and PP1?±. Moreover, while the expression of wild-type BRCA1 in Brca1-deficient cells improved cell survival after DNA damage induced by ionizing radiation (IR), expression of BRCA1 K898E proved unable to enhance cell survival. DNA damage repair mechanisms remained defective in these BRCA1 K898E-reconstituted cells, as revealed by the comet assay and IR-induced Rad51 foci formation assay. These results reflect the significance of the interaction between BRCA1 and PP1, and indicate that the K898E variant may render carriers susceptible to DNA damage and malignant transformation.
Other Subjects
BRCA1 protein; BRCA1 protein, human; Rad51 protein; RAD51 protein, human; amino acid sequence; animal; binding site; chemistry; Chlorocebus aethiops; COS 1 cell line; DNA repair; genetic association; genetic predisposition; genetics; hereditary breast and ovarian cancer syndrome; metabolism; missense mutation; molecular genetics; mouse; nucleotide sequence; protein tertiary structure; tumor cell line; Amino Acid Sequence; Animals; Binding Sites; BRCA1 Protein; Cell Line, Tumor; Cercopithecus aethiops; Conserved Sequence; COS Cells; DNA Repair; Genetic Association Studies; Genetic Predisposition to Disease; Hereditary Breast and Ovarian Cancer Syndrome; Mice; Molecular Sequence Data; Mutation, Missense; Protein Structure, Tertiary; Rad51 Recombinase
Type
journal article