Targeting of the molecular chaperone oxygen-regulated protein 150 (ORP150) to mitochondria and its induction by cellular stress
Targeting of the molecular chaperone oxygen-regulated protein 150 (ORP150) to mitochondria and its induction by cellular stress
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DOI：
10.1152/ajpcell.00400.2007
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发表时间：
2008-02-01
影响因子：
5.5
通讯作者：
Schnellmann, Rick G.
中科院分区：
文献类型：
--
作者：
Arrington, David D.;Schnellmann, Rick G.
氧调节蛋白150（ORP 150）是一种诱导型内质网（ER）伴侣分子，在多次细胞损伤后上调，在肾脏、神经和心脏缺血再灌注损伤模型中具有细胞保护作用。ORP 150也被证明在细胞Ca 2+稳态中起作用，并反过来调节钙蛋白酶活性。在这项研究中，我们在整个大鼠肾皮质线粒体和基质组分中鉴定了ORP 150，证明了ORP 150-GFP构建体对NIH-3 T3细胞线粒体的靶向作用，并表明ORP 150的NH 2-末端13个氨基酸足以进行这种易位。ORP 150的表达受抗C/增强子结合蛋白同源蛋白（CHOP）/GADD 153转录因子的调控，在低氧、血清饥饿、脯氨酰羟化酶抑制剂二甲氧酰甘氨酸、衣霉素、乙锭、溴化铵和2-脱氧葡萄糖等应激条件下，COS-7细胞线粒体和内质网中ORP 150的表达水平均升高。在COS-7细胞中，通过表达鸟氨酸转氨甲酰酶突变体（Delta OTC）诱导线粒体特异性应激反应增加了线粒体ORP 150水平和线粒体钙蛋白酶活性。为了确定线粒体ORP 150和线粒体钙蛋白酶10是否相互作用，大鼠皮质线粒体暴露于Ca 2+导致ORP 150以钙蛋白酶依赖性方式裂解，揭示ORP 150是底物，可能受钙蛋白酶10调节。这些数据揭示了ORP 150的新的细胞定位，并且线粒体ORP 150响应于线粒体和ER应激而被CHOP/GADD 153上调。我们的数据还表明，ORP 150是线粒体钙蛋白酶10的底物。
Oxygen-regulated protein 150 (ORP150) is an inducible endoplasmic reticulum (ER) chaperone molecule that is upregulated after numerous cellular insults and has a cytoprotective role in renal, neural, and cardiac models of ischemia-reperfusion injury. ORP150 also has been shown to play a role in cellular Ca2+ homeostasis, and in turn, regulating calpain activity. In this study, we identified ORP150 in whole rat renal cortical mitochondria and matrix fractions, demonstrated the targeting of an ORP150-GFP construct to the mitochondria of NIH-3T3 cells, and showed that the NH2-terminal 13 amino acids of ORP150 are sufficient for this translocation. ORP150 expression was found to be regulated by the anti-C/enhancer-binding protein homologous protein (CHOP)/GADD153 transcription factor and ORP150 levels increased in the mitochondria and ER of COS-7 cells after diverse stresses, including hypoxia, serum starvation, prolyl hydroxylase inhibition with dimethyloxaloylglycine, and exposure to tunicamycin, ethidium, bromide, and 2-deoxyglucose. Induction of the mitochondrial specific stress response in COS-7 cells through expression of an ornithine transcarbamylase mutant (Delta OTC) increased mitochondrial ORP150 levels and mitochondrial calpain activity. To determine whether mitochondrial ORP150 and mitochondrial calpain 10 interact, rat cortical mitochondria exposed to Ca2+ resulted in ORP150 cleavage in a calpain inhibitor-dependent manner, revealing that ORP150 is a substrate and may be regulated by calpain 10. These data reveal a novel cellular localization for ORP150 and that mitochondrial ORP150 is upregulated by CHOP/GADD153 in response to mitochondrial and ER stress. Our data also reveal that ORP150 is a substrate for mitochondrial calpain 10.