Cytochrome c peroxidase is a mitochondrial heme-based H2O2 sensor that modulates antioxidant defense
Cytochrome c peroxidase is a mitochondrial heme-based H2O2 sensor that modulates antioxidant defense
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DOI：
10.1016/j.freeradbiomed.2013.06.037
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发表时间：
2013-12-01
影响因子：
7.4
通讯作者：
English, Ann M.
中科院分区：
文献类型：
--
作者：
Martins, Dorival;Kathiresan, Meena;English, Ann M.
过氧化氢（H2 O2）是一种关键的信号分子，也可诱导细胞凋亡。因此，细胞必须快速感知并严格控制H2 O2水平。表征良好的细胞对外源性H2 O2的反应涉及特定的细胞溶质蛋白基硫醇的氧化，但对线粒体呼吸产生的H2 O2的感知描述较少。在这里，我们提供了大量的生化证据表明，赫恩酶Ccp 1（细胞色素c过氧化物酶），这是针对膜间隙，功能主要是作为一个线粒体过氧化氢传感和信号蛋白在酿酒酵母。Ccp 1的传感作用的关键证据是显着更高的H2 O2积累在ccp 1-null细胞（ccp 1 Delta）与ccp 1（W191 F）细胞产生催化失活的Ccp 1（W191 F）的变体。事实上，细胞内H2 O2水平（ccp 1 Delta >野生型> ccp 1（W191 F））与线粒体（和过氧化物酶体）血红素过氧化氢酶Cta 1的活性呈负相关（ccp 1 <野生型<ccp 1（W191 F））。线粒体Sod 2活性在三种菌株中也不同（ccp 1 Delta >野生型> ccp 1（W191 F）），并且ccp 1 Delta细胞表现出低的超氧化物水平。值得注意的是，Ccp 1（W191 F）是一种比野生型Ccp 1更持久的H2 O2信号蛋白，这种增强的线粒体H2 O2信号降低了ccp 1（W191 F）细胞的线粒体适应性。然而，这些细胞是完全保护从弹丸（0.4 mM）的外源性H2 O2后加入12小时的生长，而ccp 1 δ细胞的活力下降到20%以下，这另外与Ccp 1与Yap 1依赖H2 O2信号。结合，我们的研究结果强烈暗示Ccp 1，独立于其过氧化物酶活性，在线粒体H2 O2传感和信号，以维持活性氧物种的稳态。(C)2013 Elsevier Inc. All rights reserved.
Hydrogen peroxide (H2O2) is a key signaling molecule that also induces apoptosis. Thus, cells must rapidly sense and tightly control H2O2 levels. Well-characterized cellular responses to exogenous H2O2 involve oxidation of specific cytosolic protein-based thiols but sensing of H2O2 generated by mitochondrial respiration is less well described. Here we provide substantial biochemical evidence that the herne enzyme Ccp1 (cytochrome c peroxidase), which is targeted to the intermembrane space, functions primarily as a mitochondrial H2O2 sensing and signaling protein in Saccharomyces cerevisiae. Key evidence for a sensing role for Ccp1 is the significantly higher H2O2 accumulation in ccp1-null cells (ccp1 Delta) vs ccp1(W191F) cells producing the catalytically inactive Ccp1(W191F) variant. In fact, intracellular H2O2 levels (ccp1 Delta > wildtype > ccp1(W191F)) correlate inversely with the activity of the mitochondrial (and peroxisomal) heme catalase, Cta1 (ccp1 < wildtype < ccp1(W191F)). Mitochondrial Sod2 activity also varies in the three strains (ccp1 Delta > wildtype > ccp1(W191F)) and ccp1 Delta cells exhibit low superoxide levels. Notably, Ccp1(W191F) is a more persistent H2O2 signaling protein than wild-type Ccp1, and this enhanced mitochondrial H2O2 signaling decreases the mitochondrial fitness of ccp1(W191F) cells. However, these cells are fully protected from a bolus (0.4 mM) of exogenous H2O2 added after 12 h of growth, whereas the viability of ccp1 Delta cells drops below 20%, which additionally associates Ccp1 with Yap1-dependent H2O2 signaling. Combined, our results strongly implicate Ccp1, independent of its peroxidase activity, in mitochondrial H2O2 sensing and signaling to maintain reactive oxygen species homeostasis. (C) 2013 Elsevier Inc. All rights reserved.