Role of calcium and superoxide dismutase in sensitizing mitochondria to peroxynitrite-induced permeability transition
Role of calcium and superoxide dismutase in sensitizing mitochondria to peroxynitrite-induced permeability transition
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DOI：
10.1152/ajpheart.00742.2003
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发表时间：
2004-01-01
影响因子：
4.8
通讯作者：
Darley-Usmar, VM
中科院分区：
文献类型：
--
作者：
Brookes, PS;Darley-Usmar, VM
线粒体通透性过渡孔（PTP）是一种响应Ca2+和过氧亚硝酸盐（ONOO-）等氧化剂而组装和打开的膜蛋白复合物。打开PTP与细胞色素c的释放有关，细胞色素c参与下游凋亡信号传导。然而，在促进PTP的氧化剂和Ca2+之间的协同相互作用的分子基础知之甚少，并在本研究中得到解决。在离体大鼠肝脏线粒体中，我们发现离体大鼠肝脏线粒体暴露于Ca2+的时间是决定ONOO-对PTP影响的关键因素。具体而言，单独添加Ca2+或ONOO-然后再添加Ca2+，引起类似的低水平PTP开放，而ONOO-单独无效。相比之下，添加Ca2+和ONOO-诱导广泛的PTP开放和细胞色素c释放。有趣的是，Cu/ Zn-超氧化物歧化酶通过一种独立于其催化活性的机制增强了孔隙的开度。这些数据与Ca2+揭示的分子靶标现在与ONOO-反应的模型一致。为了验证这一假设，我们测定了单独暴露于ONOO-或Ca2+再暴露于ONOO-的线粒体中的酪氨酸硝化，并使用蛋白质组学分析了线粒体膜蛋白。这些研究表明Ca2+揭示的蛋白质靶点包括脱氢酶和含辅酶a的酶。这些数据在线粒体、Ca2+和ONOO-在凋亡信号传导中的作用的背景下进行了讨论。
The mitochondrial permeability transition pore ( PTP) is a membrane protein complex assembled and opened in response to Ca2+ and oxidants such as peroxynitrite ( ONOO-). Opening the PTP is mechanistically linked to the release of cytochrome c, which participates in downstream apoptotic signaling. However, the molecular basis of the synergistic interactions between oxidants and Ca2+ in promoting the PTP are poorly understood and are addressed in the present study. In isolated rat liver mitochondria, it was found that the timing of the exposure of the isolated rat liver mitochondria to Ca2+ was a critical factor in determining the impact of ONOO- on PTP. Specifically, addition of Ca2+ alone, or ONOO- and then Ca2+, elicited similar low levels of PTP opening, whereas ONOO- alone was ineffective. In contrast, addition of Ca2+ and then ONOO- induced extensive PTP opening and cytochrome c release. Interestingly, Cu/ Zn- superoxide dismutase enhanced pore opening through a mechanism independent of its catalytic activity. These data are consistent with a model in which Ca2+ reveals a molecular target that is now reactive with ONOO-. As a test of this hypothesis, tyrosine nitration was determined in mitochondria exposed to ONOO- alone or to Ca2+ and then ONOO-, and mitochondrial membrane proteins were analyzed using proteomics. These studies suggest protein targets revealed by Ca2+ include dehydrogenases and CoA- containing enzymes. These data are discussed in the context of the role of mitochondria, Ca2+, and ONOO- in apoptotic signaling.