ERO1-independent production of H2O2 within the endoplasmic reticulum fuels Prdx4-mediated oxidative protein folding.
ERO1-independent production of H2O2 within the endoplasmic reticulum fuels Prdx4-mediated oxidative protein folding.
复制标题
DOI：
10.1083/jcb.201506123
复制
发表时间：
2015-10-26
期刊：
影响因子：
--
通讯作者：
Avezov E
中科院分区：
文献类型：
--
作者：
Konno T;Pinho Melo E;Lopes C;Mehmeti I;Lenzen S;Ron D;Avezov E
追踪过氧化氢在隔室之间的平衡动力学，揭示了内质网意外的分离，并暗示了迄今未被怀疑的局部过氧化氢来源。内质网(ER)定位的过氧化还蛋白4(PRDX4)支持缺乏内质网氧化酶1(ERO1)的真核细胞中二硫键的形成。促进PRDX4介导的二硫键形成的过氧化氢的来源仍然是一个谜，因为ERO1被认为是内质网管腔中过氧化氢(H_2O_2)的主要产生者。我们报告了一种简单的动力学技术来跟踪细胞间的过氧化氢平衡，表明内质网相对独立于细胞质或线粒体的过氧化氢池。此外，在缺乏ERO1的细胞中，表达内质网适应的过氧化氢酶来降解腔内H_2O_2可减弱PRDX4介导的二硫键的形成，而胞浆或线粒体中H_2O_2的耗尽则没有类似的作用。在缺乏ERO1和PRDX4的细胞中，ER过氧化氢酶不影响缓慢的残余二硫键的形成。这些观察表明，PRDX4利用了一种迄今未被认识的过氧化氢的腔来源，以及一条平行的缓慢的非依赖过氧化氢的途径来形成二硫化物。
Tracking the kinetics of equilibration of H2O2 between compartments reveals unexpected isolation of the endoplasmic reticulum and hints at a hitherto unsuspected local source of peroxide. The endoplasmic reticulum (ER)–localized peroxiredoxin 4 (PRDX4) supports disulfide bond formation in eukaryotic cells lacking endoplasmic reticulum oxidase 1 (ERO1). The source of peroxide that fuels PRDX4-mediated disulfide bond formation has remained a mystery, because ERO1 is believed to be a major producer of hydrogen peroxide (H2O2) in the ER lumen. We report on a simple kinetic technique to track H2O2 equilibration between cellular compartments, suggesting that the ER is relatively isolated from cytosolic or mitochondrial H2O2 pools. Furthermore, expression of an ER-adapted catalase to degrade lumenal H2O2 attenuated PRDX4-mediated disulfide bond formation in cells lacking ERO1, whereas depletion of H2O2 in the cytosol or mitochondria had no similar effect. ER catalase did not effect the slow residual disulfide bond formation in cells lacking both ERO1 and PRDX4. These observations point to exploitation of a hitherto unrecognized lumenal source of H2O2 by PRDX4 and a parallel slow H2O2-independent pathway for disulfide formation.