Investigating the Molecular Details of the Interaction between Two Tumor Suppressing Proteins, BRCA1 and P53

Abstract

Breast cancer type 1 protein (BRCA1) is a major risk factor for developing breast cancer. The BRCA1 protein is involved in many essential cellular pathways, including DNA double-strand break repair, cell cycle checkpoint control and induction of apoptosis. The tumor protein p53 is a major tumor suppressor that has similar functions with BRCA1. These two proteins were found to interact with each other in vivo, but it is unclear whether BRCA1 directly binds to p53 and what is the biological relevance of this interaction. We hypothesized that there is a physical interaction-- direct amino acid contacts-- between BRCA1 (amino acid 772-1292) and p53 (amino acid 311-393). We utilized cloning and protein purification to obtain overlapping protein constructs of the two proteins and developed a pull-down assay to investigate their direct binding. Further work is needed to optimize the conditions for expression, purification and pull-down assay to draw definitive conclusions regarding the binding regions of BRCA1 and p53.