Real-time monitoring BimL interacting with Bcl-xL during UV-induced apoptosis

BimL is an important BH3-only protein, whose function is act upstream of apoptosis. However, the molecular role of BimL in apoptosis remains not well understood. Our previous reported shown that BimL was involved in the UV irradiation-induced apoptosis. Based on RNAi, FRET and co-immunoprecipitation techniques, in this study, in addition to well determine the role of BimL in UV-induced apoptosis, we particularly monitor the relationship between BimL and Bcl-xL during UV irradiation in both living and extracted cells. First, Knockdown of BimL by a small hairpin RNA confirmed this BH3-only member play an important role in the UV-induced apoptosis. Moreover, using FRET technique, we further revealed that BimL directly binds to Bcl-xL, and the combination of these complexes became more and more obviously during UV irradiation, which results were further highlighted by co-immunoprecipitation analysis. Thus, the data suggested that BimL directly binds Bcl-xL and play an important role during UV irradiation-induced apoptosis through suppresses the function of Bcl-xL.