Qu Jing, Liu Guang-Hui, Huang Bo, Chen Chang
National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, and Graduate School of the Chinese Academy of Sciences, Beijing, China.
Nucleic Acids Res. 2007;35(8):2522-32. doi: 10.1093/nar/gkl1163. Epub 2007 Apr 1.
Apurinic/apyrimidinic endonuclease 1/redox effector factor-1 (APE1/Ref-1, abbreviated as APE1) is a molecule with dual functions in DNA repair and redox regulation of transcription factors. Accumulated work has shown that the biological activities of APE1 are sensitive to oxidative stress; however, whether APE1 functions can be regulated by nitrosative stress remains unknown. In this investigation, we found that S-nitrosoglutathion (GSNO), a nitric oxide donor and also an S-nitrosating agent, effectively stimulated nuclear export of APE1 in a CRM1-independent manner. This nuclear-cytoplasmic translocation was dependent on S-nitrosation modification of APE1, as simultaneous mutation of S-nitrosation target sites Cys93 and Cys310 completely abrogated the cytoplasmic redistribution. The translocation process was reversal and specific, as it could be reversed by reductive reagents, but could not be mimicked by H2O2. In structure, the region aa.64-80 and the beta-strand aa.311-316 in proximity to Cys93 and Cys310 were important for GSNO-induced APE1 relocalization. In addition, a defect of importin-mediated nuclear import pathway was found in the NO-insulted cells, and p50 and HDAC2 were identified as APE1 nuclear export inhibitory proteins. Together, this study may provide a novel molecular mechanism, which links nitrosative stress to APE1-associated physiological and pathological processes.
脱嘌呤/脱嘧啶内切酶1/氧化还原效应因子-1（APE1/Ref-1，简称为APE1）是一种在DNA修复和转录因子氧化还原调节中具有双重功能的分子。大量研究表明，APE1的生物学活性对氧化应激敏感；然而，APE1的功能是否能被亚硝化应激调节仍不清楚。在本研究中，我们发现一氧化氮供体及亚硝化剂S-亚硝基谷胱甘肽（GSNO）能以不依赖CRM1的方式有效刺激APE1的核输出。这种核质转运依赖于APE1的亚硝化修饰，因为亚硝化靶点Cys93和Cys310的同时突变完全消除了细胞质中的重新分布。转运过程是可逆且特异的，因为它可以被还原试剂逆转，但不能被H2O2模拟。在结构上，靠近Cys93和Cys310的aa.64-80区域和β链aa.311-316对GSNO诱导的APE1重新定位很重要。此外，在NO损伤的细胞中发现了输入蛋白介导的核输入途径缺陷，并且p50和HDAC2被鉴定为APE1核输出抑制蛋白。总之，本研究可能提供了一种新的分子机制，将亚硝化应激与APE1相关的生理和病理过程联系起来。
