BH3-Like Motif Containing Protein, Cell Death Inducer (BLID)

The deduced 108-amino acid protein has a calculated molecular mass of about 12 kD. The N terminus contains a domain similar to the BH3 domain of proapoptotic proteins. Western blot analysis detected endogenous BRCC2 in all human cell lines tested. In COS-1 and HeLa cells, BRCC2 was predominantly a cytosolic protein, with lower abundance in mitochondria.In a human prostate cancer cell line, BRCC2-induced DNA fragmentation was blocked by coexpression of the antiapoptotic molecule BCLXL or by a broad-range caspase inhibitor. BRCC2 expression correlated with activation of CASP3 and CASP9. BRCC2 with an N-terminal deletion of the BH3-like domain failed to induce apoptosis. Treatment of HeLa cells with doxorubicin or hydrogen peroxide led to an increase in the mitochondrial level of endogenous BRCC2.