Mitochondrial targeting of the human peptide methionine sulfoxide reductase (MSRA), an enzyme-involved in the repair of oxidized proteins
Mitochondrial targeting of the human peptide methionine sulfoxide reductase (MSRA), an enzyme-involved in the repair of oxidized proteins
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DOI：
10.1096/fj.01-0737fje
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发表时间：
2002-04-01
期刊：
影响因子：
4.8
通讯作者：
Heinemann, SH
中科院分区：
文献类型：
--
作者：
Hansel, A;Kuschel, L;Heinemann, SH
肽段蛋氨酸亚砜还原酶（MSRA）催化蛋氨酸亚砜还原为蛋氨酸。这种广泛表达的酶是氧化损伤蛋白的重要修复机制，氧化损伤蛋白在某些退行性疾病和衰老过程中积累。此外，还讨论了参与监管过程的问题。在这里，我们解决的问题，酶的不同功能是如何反映在其亚细胞定位。将人类版本的MSRA与在各种哺乳动物细胞系中表达的增强绿色荧光蛋白融合，我们在线粒体中发现了明显的定位。n端23个氨基酸残基包含线粒体靶向的信号。活性试验表明它们不是酶功能所必需的。采用免疫组织化学方法，用MSRA特异性抗体验证小鼠和大鼠肝脏切片中MSRA的线粒体定位。通过预包埋免疫染色和电镜观察证实，该蛋白位于线粒体基质中。线粒体是活性氧（ROS）的主要来源。因此，MSRA必须被认为是线粒体中ROS释放普遍减少的重要手段。
Peptide methionine sulfoxide reductase (MSRA) catalyzes the reduction of methionine sulfoxide to methionine. This widely expressed enzyme constitutes an important repair mechanism for oxidatively damaged proteins, which accumulate during the manifestation of certain degenerative diseases and aging processes. In addition, it is discussed to be involved in regulatory processes. Here we address the question of how the enzyme's diverse functions are reflected in its subcellular localization. Using fusions of the human version of MSRA with the enhanced green fluorescence protein expressed in various mammalian cell lines, we show a distinct localization at mitochondria. The N-terminal 23 amino acid residues contain the signal for this mitochondrial targeting. Activity tests showed that they are not required for enzyme function. Mitochondrial localization of native MSRA in mouse and rat liver slices was verified with an MSRA-specific antibody by using immunohistochemical methods. The protein was located in the mitochondrial matrix, as demonstrated by using pre-embedding immunostaining and electron microscopy. Mitochondria are the major source of reactive oxygen species (ROS). Therefore, MSRA has to be considered an important means for the general reduction of ROS release from mitochondria.