Human Cytochrome P450 2E1 Mutations That Alter Mitochondrial Targeting Efficiency and Susceptibility to Ethanol-induced Toxicity in Cellular Models
Human Cytochrome P450 2E1 Mutations That Alter Mitochondrial Targeting Efficiency and Susceptibility to Ethanol-induced Toxicity in Cellular Models
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DOI：
10.1074/jbc.m113.452367
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发表时间：
2013-05-03
影响因子：
4.8
通讯作者：
Avadhani, Narayan G.
中科院分区：
文献类型：
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作者：
Bansal, Seema;Anandatheerthavarada, Hindupur K.;Avadhani, Narayan G.
已知细胞色素P450 2 E1（CYP 2 E1）的5 '上游调控区以及蛋白质编码区中的人类多态性与若干疾病相关，包括癌症和酒精肝毒性。在这项研究中，我们报告了CYP 2 E1的N-末端蛋白靶向区域的新突变，这些突变显著影响蛋白的亚细胞定位。变体W23 R/W30 R蛋白（称为W23/30 R）优先靶向线粒体，但对内质网的靶向非常差，而L32 N蛋白优先靶向内质网，对线粒体的靶向很差。这些结果解释了先前描述的靶向内质网和线粒体的双峰双磷酸酶的生理意义。稳定表达W23/30 R突变的COS-7细胞和HepG 2细胞表现出明显增加的酒精毒性，包括活性氧产生增加、呼吸功能障碍和细胞色素c氧化酶亚基和活性丧失。另一方面，表达L32 N变体的稳定细胞对酒精诱导的毒性和线粒体功能障碍的反应相对较低。这些结果进一步支持了我们以前的数据，基于涉及改变靶向的突变研究，表明靶向CYP 2 E1在酒精肝毒性中起重要作用。这些结果还提供了一个有趣的新的链接，影响亚细胞分布的CYP 2 E1与酒精诱导的毒性遗传变异。
Human polymorphisms in the 5'-upstream regulatory regions and also protein coding regions of cytochrome P450 2E1 (CYP2E1) are known to be associated with several diseases, including cancer and alcohol liver toxicity. In this study, we report novel mutations in the N-terminal protein targeting regions of CYP2E1 that markedly affect subcellular localization of the protein. Variant W23R/W30R protein (termed W23/30R) is preferentially targeted to mitochondria but very poorly to the endoplasmic reticulum, whereas the L32N protein is preferentially targeted to the endoplasmic reticulum and poorly to mitochondria. These results explain the physiological significance of bimodal CYP targeting to the endoplasmic reticulum and mitochondria previously described. COS-7 cells and HepG2 cells stably expressing W23/30R mutations showed markedly increased alcohol toxicity in terms of increased production of reactive oxygen species, respiratory dysfunction, and loss of cytochrome c oxidase subunits and activity. Stable cells expressing the L32N variant, on the other hand, were relatively less responsive to alcohol-induced toxicity and mitochondrial dysfunction. These results further support our previous data, based on mutational studies involving altered targeting, indicating that mitochondria-targeted CYP2E1 plays an important role in alcohol liver toxicity. The results also provide an interesting new link to genetic variations affecting subcellular distribution of CYP2E1 with alcohol-induced toxicity.