NADH oxidase activity of mitochondrial apoptosis-inducing factor
NADH oxidase activity of mitochondrial apoptosis-inducing factor
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DOI：
10.1074/jbc.m010498200
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发表时间：
2001-05-11
影响因子：
4.8
通讯作者：
Susin, SA
中科院分区：
文献类型：
--
作者：
Miramar, MD;Costantini, P;Susin, SA
凋亡诱导因子（Apoptosis-inducing factor，AIF）是一种线粒体黄素蛋白，在细胞凋亡过程中转位至细胞核，引起染色质浓缩和DNA大规模断裂。在这里，我们报告的生化表征AIF的氧化还原活性。从线粒体中纯化的天然AIF和从细菌中纯化的重组AIF（AIF Delta 1 -120）表现出NADH氧化酶活性，而形成超氧阴离子（O-2（-））。AIF Delta 1 -120是57 kDa的单体，每摩尔蛋白质含有1摩尔非共价结合的FAD。缺乏FAD的ApoATF Delta 1 -120没有NADH氧化酶活性。然而，当显微注射到完整细胞的细胞质中时，天然AIF Delta 1 - 120、apoAIF Delta 1 -120和重构的（含FAD的）holoAIF Delta 1 -120蛋白表现出类似的凋亡诱导潜力。通过外部加入超氧化物歧化酶或FAD与diphenyleneiodonium的共价衍生化来抑制氧化还原功能，未能影响AIF Delta 1 -120在无细胞系统中对纯化的细胞核进行评估的促凋亡功能。相反，用巯基试剂对氯汞苯磺酸阻断AIF Delta 1 -120的促凋亡功能并不影响其NADH氧化酶活性。总之，这些数据表明，AIF具有显著的氧化还原酶活性，这可以与其诱导骨质疏松症的功能分离。
Apoptosis-inducing factor (AIF) is a mitochondrial flavoprotein, which translocates to the nucleus during apoptosis and causes chromatin condensation and large scale DNA fragmentation. Here we report the biochemical characterization of AIF's redox activity. Natural AIF purified from mitochondria and recombinant AIF purified from bacteria (AIF Delta1-120) exhibit NADH oxidase activity, whereas superoxide anion (O-2(-)) is formed. AIF Delta1-120 is a monomer of 57 kDa containing 1 mol of noncovalently bound FAD/mol of protein. ApoATF Delta1-120, which lacks FAD, has no NADH oxidase activity. However, native AIF Delta1-120, apoAIF Delta1-120, and the reconstituted (FAD-containing) holoAIF Delta1-120 protein exhibit a similar apoptosis-inducing potential when microinjected into the cytoplasm of intact cells. inhibition of the redox function, by external addition of superoxide dismutase or covalent derivatization of FAD with diphenyleneiodonium, failed to affect the apoptogenic function of AIF Delta1-120 assessed on purified nuclei in a cell-free system. Conversely, blockade of the apoptogenic function of AIF Delta1-120 with the thiol reagent para-chloromercuriphenylsulfonic acid did not affect its NADH oxidase activity. Altogether, these data indicate that AIF has a marked oxidoreductase activity which can be dissociated from its apoptosis-inducing function.