Ubiquitin facilitates a quality-control pathway that removes damaged chloroplasts.
Ubiquitin facilitates a quality-control pathway that removes damaged chloroplasts.
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DOI：
10.1126/science.aac7444
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发表时间：
2015-10-23
期刊：
影响因子：
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通讯作者：
Chory J
中科院分区：
文献类型：
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作者：
Woodson JD;Joens MS;Sinson AB;Gilkerson J;Salomé PA;Weigel D;Fitzpatrick JA;Chory J
叶绿体和线粒体产生的能量会导致持续的氧化损伤。正常运作的光合作用细胞需要质量控制机制来翻转和降解被活性氧(ROS)破坏的叶绿体。在这里，我们产生了一个条件致死的拟南芥突变体，它在叶绿体中积累了过量的原卟啉IX，并产生了单线态氧。受损的叶绿体随后被泛素化并选择性地降解。遗传筛选表明，植物U-box 4(PUB4)E3泛素连接酶在这一过程中是必需的。Pub4-6突变体在胁迫适应和寿命方面存在缺陷。因此，我们已经确定了导致ROS过量产生的叶绿体被靶向移除的信号。
Energy production by chloroplasts and mitochondria causes constant oxidative damage. A functioning photosynthetic cell requires quality-control mechanisms to turn over and degrade chloroplasts damaged by reactive oxygen species (ROS). Here, we generated a conditionally lethal Arabidopsis mutant that accumulated excess protoporphyrin IX in the chloroplast and produced singlet oxygen. Damaged chloroplasts were subsequently ubiquitinated and selectively degraded. A genetic screen identified the plant U-box 4 (PUB4) E3 ubiquitin ligase as being necessary for this process. pub4-6 mutants had defects in stress adaptation and longevity. Thus, we have identified a signal that leads to the targeted removal of ROS-overproducing chloroplasts.