Abstract
According to the statistics from the Chang Gung Memorial Hospital, the incidence of breast cancer is the second highest in women, only next to cervical cancer. The protein BRCA1 (Breast cancer-associated gene 1), which is a breast tumor suppressor, interacts with the protein BARD1 (BRCA1-associated RING domain protein), resulting in the formation of a heterodimeric complex that has E3 ubiquitin ligase activity and plays a central role in cell cycle checkpoint control, DNA repair, and microtubule (MT) aster formation. The protein OLA1 (Obg-like ATPase 1) is a new binding partner of BRCA1/BARD1. A previous study found that OLA1 mutation (E168Q), which was observed in breast cancer cell line, failed to bind BRCA1. However, the structural basis and functional consequences of the interaction of OLA1 with BRCA1/BARD1 are unknown yet. Our goal is to understand the molecular basis of the interaction of OLA1 with BRCA1/BARD1. We used NMR TROSY-HSQC experiments to detect interaction of OLA1 and BRCA1/BARD1 in the apo and ATP state. We used ATPase assays in combination with site-directed mutagenesis to demonstrate a potential OLA1 binding site on BARD1 BRCT. Structural information derived from this study provides a new insight to fundamental as well as breast cancer biology.