Yang J, Liu X, Bhalla K, Kim C N, Ibrado A M, Cai J, Peng T I, Jones D P, Wang X
Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, USA.
Science. 1997 Feb 21;275(5303):1129-32. doi: 10.1126/science.275.5303.1129.
Bcl-2 is an integral membrane protein located mainly on the outer membrane of mitochondria. Overexpression of Bcl-2 prevents cells from undergoing apoptosis in response to a variety of stimuli. Cytosolic cytochrome c is necessary for the initiation of the apoptotic program, suggesting a possible connection between Bcl-2 and cytochrome c, which is normally located in the mitochondrial intermembrane space. Cells undergoing apoptosis were found to have an elevation of cytochrome c in the cytosol and a corresponding decrease in the mitochondria. Overexpression of Bcl-2 prevented the efflux of cytochrome c from the mitochondria and the initiation of apoptosis. Thus, one possible role of Bcl-2 in prevention of apoptosis is to block cytochrome c release from mitochondria.
Bcl-2是一种主要位于线粒体外膜的整合膜蛋白。Bcl-2的过表达可防止细胞在多种刺激下发生凋亡。细胞溶质细胞色素c是启动凋亡程序所必需的，这表明Bcl-2与通常位于线粒体膜间隙的细胞色素c之间可能存在联系。发现正在经历凋亡的细胞其细胞溶质中的细胞色素c升高，而线粒体中的相应减少。Bcl-2的过表达可防止细胞色素c从线粒体流出以及凋亡的启动。因此，Bcl-2在预防凋亡中的一种可能作用是阻止细胞色素c从线粒体释放。
