Bcl-2 family proteins have been reported previously to play important roles in the mitochondrial apoptotic pathway.Particularly,Bmbuffy has been identified as a key homologue of Bcl-2 in silkworm; however,its exact function is unknown.In this study,we investigated the role of Bmbuffy in hydroxycamptothecine(HCPT)-induced apoptosis of BmN-SWU1 cells.By conducting confocal microscopy studies,we found that Bmbuffy is located on the outer membrane of mitochondria and endoplasmic reticulum(ER).