Lithgow T, van Driel R, Bertram J F, Strasser A
Department of Biochemistry, La Trobe University, Bundoora, Victoria, Australia.
Cell Growth Differ. 1994 Apr;5(4):411-7.
The protein product of the oncogene bcl-2 is a potent inhibitor of apoptotic cell death. The Bcl-2 protein has variously been reported to reside in the nuclear envelope and endoplasmic reticulum or exclusively in the inner membrane of mitochondria. We therefore undertook a detailed analysis of the intracellular distribution of Bcl-2 by immunofluorescence, immunogold electron microscopy, and subcellular fractionation in three mouse cell lines expressing a human bcl-2 transgene and measured its importation into isolated mitochondria. By these methods, the protein was localized to the nuclear envelope, the endoplasmic reticulum, and the outer mitochondrial membrane. Any proposal for the mechanism by which Bcl-2 inhibits apoptosis must therefore accommodate the fact that Bcl-2 localizes to cytoplasmic membranes facing the cytosol.
癌基因bcl-2的蛋白质产物是凋亡细胞死亡的有效抑制剂。据报道，Bcl-2蛋白存在于核膜和内质网中，或仅存在于线粒体内膜中。因此，我们通过免疫荧光、免疫金电子显微镜和亚细胞分级分离法，对三种表达人bcl-2转基因的小鼠细胞系中Bcl-2的细胞内分布进行了详细分析，并测定了其导入分离线粒体的情况。通过这些方法，该蛋白定位于核膜、内质网和线粒体外膜。因此，任何关于Bcl-2抑制细胞凋亡机制的提议都必须考虑到Bcl-2定位于面向胞质溶胶的细胞质膜这一事实。
