Bnip3 functions as a mitochondrial sensor of oxidative stress during myocardial ischemia and reperfusion
Bnip3 functions as a mitochondrial sensor of oxidative stress during myocardial ischemia and reperfusion
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DOI：
10.1152/ajpheart.00552.2008
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发表时间：
2008-11-01
影响因子：
4.8
通讯作者：
Gustafsson, Asa B.
中科院分区：
文献类型：
--
作者：
Kubli, Dieter A.;Quinsay, Melissa N.;Gustafsson, Asa B.
Kubli DA，Quinsay MN，Huang C，Lee Y，Gustafsson AB。 Bnip3 在心肌缺血和再灌注过程中充当氧化应激的线粒体传感器。 Am J Physiol Heart Circ Physiol 295：H2025-H2031，2008。首次发表于 2008 年 9 月 12 日； doi：10.1152/ajpheart.00552.2008。 - Bcl-2/腺病毒 E1B 19-kDa 蛋白相互作用蛋白 3 (Bnip3) 是促凋亡 Bcl-2 蛋白仅 Bcl-2 同源结构域 3 亚家族的成员，与心肌细胞死亡相关。在这项研究中，我们研究了调节 Bnip3 活性的潜在机制。我们发现 Bnip3 形成一种 DTT 敏感的同型二聚体，在心肌缺血再灌注 (I/R) 后增加。抗氧化剂 N-乙酰半胱氨酸的存在减少了 I/R 诱导的 Bnip3 同二聚化。 Bnip3 在细胞中的过度表达表明，大多数外源 Bnip3 以 DTT 敏感的同二聚体形式存在，与细胞死亡增加相关。相比之下，内源性 Bnip3 在正常条件下主要以单体形式存在于心脏中。 Bnip3 蛋白序列的筛选显示在第 64 位有一个保守的半胱氨酸残基。该半胱氨酸突变为丙氨酸 (Bnip3C64A) 或删除 NH2 末端（氨基酸 1-64）会导致 Bnip3 的细胞死亡活性降低。此外，COOH末端跨膜结构域中的组氨酸残基突变为丙氨酸（Bnip3H173A）几乎完全抑制了Bnip3的细胞死亡活性。 Bnip3C64A 与 Bnip3 相互作用的能力降低，而 Bnip3H173A 完全无法与 Bnip3 相互作用，表明同源二聚化对于 Bnip3 功能很重要。 I/R 的结果是产生活性氧和蛋白质氧化，从而促进蛋白质之间二硫键的形成。因此，这些实验表明 Bnip3 作为氧化还原传感器发挥作用，其中增加的氧化应激通过 NH2 末端半胱氨酸残基和 COOH 末端跨膜结构域的合作诱导 Bnip3 同二聚化和激活。
Kubli DA, Quinsay MN, Huang C, Lee Y, Gustafsson AB. Bnip3 functions as a mitochondrial sensor of oxidative stress during myocardial ischemia and reperfusion. Am J Physiol Heart Circ Physiol 295: H2025-H2031, 2008. First published September 12, 2008; doi:10.1152/ajpheart.00552.2008. - Bcl-2/adenovirus E1B 19-kDa protein-interacting protein 3 (Bnip3) is a member of the Bcl-2 homology domain 3-only subfamily of proapoptotic Bcl-2 proteins and is associated with cell death in the myocardium. In this study, we investigated the potential mechanism(s) by which Bnip3 activity is regulated. We found that Bnip3 forms a DTT-sensitive homodimer that increased after myocardial ischemia-reperfusion (I/R). The presence of the antioxidant N-acetylcysteine reduced I/R-induced homodimerization of Bnip3. Overexpression of Bnip3 in cells revealed that most of exogenous Bnip3 exists as a DTT-sensitive homodimer that correlated with increased cell death. In contrast, endogenous Bnip3 existed mainly as a monomer under normal conditions in the heart. Screening of the Bnip3 protein sequence revealed a single conserved cysteine residue at position 64. Mutation of this cysteine to alanine (Bnip3C64A) or deletion of the NH2-terminus (amino acids 1-64) resulted in reduced cell death activity of Bnip3. Moreover, mutation of a histidine residue in the COOH-terminal transmembrane domain to alanine (Bnip3H173A) almost completely inhibited the cell death activity of Bnip3. Bnip3C64A had a reduced ability to interact with Bnip3, whereas Bnip3H173A was completely unable to interact with Bnip3, suggesting that homodimerization is important for Bnip3 function. A consequence of I/R is the production of reactive oxygen species and oxidation of proteins, which promotes the formation of disulfide bonds between proteins. Thus, these experiments suggest that Bnip3 functions as a redox sensor where increased oxidative stress induces homodimerization and activation of Bnip3 via cooperation of the NH2-terminal cysteine residue and the COOH-terminal transmembrane domain.