Bcl-2 expression causes redistribution of glutathione to the nucleus
Bcl-2 expression causes redistribution of glutathione to the nucleus
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DOI：
10.1073/pnas.95.6.2956
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发表时间：
1998-03-17
影响因子：
11.1
通讯作者：
Meyn, RE
中科院分区：
文献类型：
--
作者：
Voehringer, DW;McConkey, DJ;Meyn, RE
在本研究中，我们利用转Bcl2表达载体的HeLa细胞研究了Bcl2对还原型谷胱甘肽(GSH)代谢的影响，我们先前的工作表明，在缺乏GSH生物合成所必需的半胱氨酸和蛋氨酸的组织培养基中培养细胞，使GSH缺乏，导致过表达Bcl2的细胞对凋亡诱导敏感，我们报告了Bcl2也显著改变了GSH的区域化。用激光共聚焦显微镜检测细胞内GSH的分布发现，当Bcl2的表达被抑制时，GSH主要分布在胞浆中，而Bcl2的过度表达导致GSH重新定位于核内，游离核容易积累放射性标记的GSH，并维持较高的核GSH浓度，与Bcl2核蛋白水平直接相关。此外，外源性GSH阻断了受促凋亡的蛋白酶颗粒酶B作用的核的凋亡变化和caspase活性。我们的结果表明，bcl2的功能之一是促进GSH滞留到核内，从而改变核的氧化还原和阻断caspase活性以及其他以凋亡为特征的核变化。我们推测，这一机制可能有助于抑制高水平的Bcl2表达的细胞的凋亡。
In this study we used HeLa cells transfected with a conditional Bcl-2 expression construct to study the effects of Bcl-2 on reduced glutathione (GSH) metabolism, Our previous work demonstrated that depletion of GSH by culturing cells in tissue culture medium lacking the amino acids cysteine and methionine, essential for GSH biosynthesis, caused cells overexpressing Bcl-2 to become sensitized to apoptotic induction, Here we report that Bcl-2 also dramatically alters GSH compartmentalization. Cellular distribution of GSH, assayed by confocal microscopy, revealed that when Bcl-2 expression was suppressed GSH was uniformly distributed primarily in the cytosol, whereas overexpression of Bcl-2 led to a relocalization of GSH into the nucleus, Isolated nuclei readily accumulated radiolabeled GSH and maintained higher nuclear GSH concentration in direct relation to Bcl-2 nuclear protein levels, Moreover, exogenous GSH blocked apoptotic changes and caspase activity in isolated nuclei exposed to the pro-apoptotic protease granzyme B, Our results indicate that one of the functions of Bcl-2 is to promote sequestration of GSH into the nucleus, thereby altering nuclear redox and blocking caspase activity as well as other nuclear alterations characteristic of apoptosis, We speculate that this mechanism contributes to the suppression of apoptosis in cells with elevated Bcl-2 levels.