Chloroplast Biogenesis Is Regulated by Direct Action of the Ubiquitin-Proteasome System
Chloroplast Biogenesis Is Regulated by Direct Action of the Ubiquitin-Proteasome System
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DOI：
10.1126/science.1225053
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发表时间：
2012-11-02
期刊：
影响因子：
56.9
通讯作者：
Jarvis, Paul
中科院分区：
文献类型：
--
作者：
Ling, Qihua;Huang, Weihua;Jarvis, Paul
叶绿体和其他质体的发育依赖于从细胞质中输入的数千种核编码蛋白。进口是由质体外膜中的TOC（叶绿体外包膜上的易位）复合物启动的，该复合物包含多个客户特异性受体。输入的调节被认为控制着质体的蛋白质组、发育命运和功能。利用正向遗传学技术，我们鉴定出了编码叶绿体外膜环型泛素E3连接酶的拟南芥SP1。SP1蛋白与TOC复合物相关，介导TOC组分的泛素化，促进其降解。突变体sp1植物的发育转变涉及质体蛋白质组的低效率变化，表明需要重组TOC机制。因此，泛素-蛋白酶体系统作用于质体来控制它们的发育。
Development of chloroplasts and other plastids depends on the import of thousands of nucleus-encoded proteins from the cytosol. Import is initiated by TOC (translocon at the outer envelope of chloroplasts) complexes in the plastid outer membrane that incorporate multiple, client-specific receptors. Modulation of import is thought to control the plastid's proteome, developmental fate, and functions. Using forward genetics, we identified Arabidopsis SP1, which encodes a RING-type ubiquitin E3 ligase of the chloroplast outer membrane. The SP1 protein associated with TOC complexes and mediated ubiquitination of TOC components, promoting their degradation. Mutant sp1 plants performed developmental transitions that involve plastid proteome changes inefficiently, indicating a requirement for reorganization of the TOC machinery. Thus, the ubiquitin-proteasome system acts on plastids to control their development.