M phase-specific phosphorylation of BRCA2 by Polo-like kinase 1 correlates with the dissociation of the BRCA2-P/CAF complex.
BRCA2 is a breast tumor susceptibility gene encoding a 390-kDa protein with functions in maintaining genomic stability and cell cycle progression. Evidence has been accumulated to support the concept that BRCA2 has a critical role in homologous recombination of DNA double-stranded breaks by interacting with RAD51. In addition, BRCA2 may ... have chromatin modifying activity through interaction with a histone acetyltransferase protein, p300/CBP-associated factor (P/CAF). To explore how the functions of BRCA2 may be regulated, the post-translational modifications of BRCA2 throughout the cell cycle were examined. We found that BRCA2 is hyperphosphorylated specifically in M phase and becomes dephosphorylated as cells exit M phase and enter interphase. This specific phosphorylation of BRCA2 was not observed in cells treated with DNA-damaging agents. Systematic mapping of the potential mitosis specific phosphorylation sites revealed the N-terminal 284 amino acids of BRCA2 (BR-N1) as the major region of phosphorylation and mass spectrometric analysis identified two phosphopeptides that contain "phosphorylation consensus motifs" for Polo-like kinase 1 (Plk1). Phosphorylation of BR-N1 with Plk1 recapitulated the electrophoretic mobility change as seen in BR-N1 isolated from M phase cells. Plk1 interacts with BRCA2 in vivo, and mutation of Ser193, Ser205/206, and Thr203/207 to Ala in BR-N1 abolished Plk1 phosphorylation, suggesting that BRCA2 is the substrate of Plk1. Furthermore, both the hyperphosphorylated and hypophosphorylated forms of BRCA2 bind to RAD51, whereas the M phase hyperphosphorylated form of BRCA2 no longer associates with the P/CAF, suggesting that the dissociation of P/CAF-BRCA2 complex is regulated by phosphorylation. Taken together, these results implicate a potential role of BRCA2 in modulating M phase progression.
Mesh Terms:
Acetyltransferases, Amino Acid Motifs, Amino Acid Sequence, Animals, BRCA2 Protein, Blotting, Western, Cell Cycle, Cell Cycle Proteins, Cell Line, Tumor, Chromatin, DNA Damage, DNA-Binding Proteins, E1A-Associated p300 Protein, Glutathione Transferase, Green Fluorescent Proteins, Histone Acetyltransferases, Humans, Interphase, Luminescent Proteins, Mass Spectrometry, Mice, Mitosis, Models, Biological, Models, Genetic, Molecular Sequence Data, Mutation, Nuclear Proteins, Phosphoric Monoester Hydrolases, Phosphorylation, Plasmids, Precipitin Tests, Protein Binding, Protein Kinases, Protein-Serine-Threonine Kinases, Proto-Oncogene Proteins, RNA, Messenger, Rad51 Recombinase, Recombinant Proteins, Recombination, Genetic, Saccharomyces cerevisiae Proteins, Sequence Homology, Amino Acid, Trans-Activators, Transfection, Up-Regulation
Acetyltransferases, Amino Acid Motifs, Amino Acid Sequence, Animals, BRCA2 Protein, Blotting, Western, Cell Cycle, Cell Cycle Proteins, Cell Line, Tumor, Chromatin, DNA Damage, DNA-Binding Proteins, E1A-Associated p300 Protein, Glutathione Transferase, Green Fluorescent Proteins, Histone Acetyltransferases, Humans, Interphase, Luminescent Proteins, Mass Spectrometry, Mice, Mitosis, Models, Biological, Models, Genetic, Molecular Sequence Data, Mutation, Nuclear Proteins, Phosphoric Monoester Hydrolases, Phosphorylation, Plasmids, Precipitin Tests, Protein Binding, Protein Kinases, Protein-Serine-Threonine Kinases, Proto-Oncogene Proteins, RNA, Messenger, Rad51 Recombinase, Recombinant Proteins, Recombination, Genetic, Saccharomyces cerevisiae Proteins, Sequence Homology, Amino Acid, Trans-Activators, Transfection, Up-Regulation
J. Biol. Chem.
Date: Sep. 19, 2003
PubMed ID: 12815053
View in: Pubmed Google Scholar
Download Curated Data For This Publication
60620
Switch View:
- Interactions 4