The striking features of BRCA2 null cells are their hypersensitivity to DNA damaging agents and amplification of centrosomes. It has been reported that the centrosomes were amplified in a 65% of the BRCA2-/- MEFs. These data suggest that BRCA2 plays an important role in the regulation of centrosome duplication. However, how BRCA2 mediates the regulation of centrosome duplication remains undefined. One reasonable hypothesis is that BRCA2 directly interacts with some centrosomal proteins. Using a C-terminal fragment of BRCA2 as bait, we identified a novel BRCA2 binding protein, referred to as B2BP1 (BRCA2 binding protein 1). We have already demonstrated that BRCA2 can interact with B2BP1 both in vitro and in vivo. Sequence analysis of B2BP1 indicated that it is a novel gene, with a weak homology with various coiled-coil proteins, including two known centrosome proteins, pericentrin and ninein. Extensive immunofluorescence studies demonstrated that B2BP1 is a centrosomal protein, which strongly indicates a role for B2BP1 in the regulation of centrosome duplication. This predicted function of B2BP1 is well in accordance with the known functions of BRCA2. Therefore, we propose to characterize B2BP1 protein, localization, interaction and co-localization with BRCA2, and interaction with tubulins. We also propose to elucidate the role of the B2BP1-BRCA2 interaction in the normal function of centrosome (e.g. microtubule nucleation, spindle formation) and the regulation of centrosome duplication. Our finding that BRCA2 directly interacts with a centrosomal protein reveals an important link between BRCA2 and the regulation of centrosome duplication. Further characterization of B2BP1 should provide important insights into the mechanism of BRCA2 mutation-mediated tumorigenesis.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA095221-05
Application #
7276602
Study Section
Metabolic Pathology Study Section (MEP)
Program Officer
Spalholz, Barbara A
Project Start
2003-09-20
Project End
2008-08-31
Budget Start
2007-09-01
Budget End
2008-08-31
Support Year
5
Fiscal Year
2007
Total Cost
$239,605
Indirect Cost
Name
Northshore University Healthsystem
Department
Type
DUNS #
069490621
City
Evanston
State
IL
Country
United States
Zip Code
60201
Gudi, Radhika; Zou, Chaozhong; Li, Jun et al. (2011) Centrobin-tubulin interaction is required for centriole elongation and stability. J Cell Biol 193:711-25
Osmundson, Evan C; Ray, Dipankar; Moore, Finola E et al. (2008) The HECT E3 ligase Smurf2 is required for Mad2-dependent spindle assembly checkpoint. J Cell Biol 183:267-77
Zou, Chaozhong; Li, Jun; Bai, Yujie et al. (2005) Centrobin: a novel daughter centriole-associated protein that is required for centriole duplication. J Cell Biol 171:437-45
Tian, Xin-xia; Rai, Deepak; Li, Jun et al. (2005) BRCA2 suppresses cell proliferation via stabilizing MAGE-D1. Cancer Res 65:4747-53