Transorganellar complementation redefines the biochemical continuity of endoplasmic reticulum and chloroplasts
Transorganellar complementation redefines the biochemical continuity of endoplasmic reticulum and chloroplasts
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DOI：
10.1073/pnas.1306331110
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发表时间：
2013-07-16
影响因子：
11.1
通讯作者：
DellaPenna, Dean
中科院分区：
文献类型：
--
作者：
Mehrshahi, Payam;Stefano, Giovanni;DellaPenna, Dean
生育酚是质体中合成和定位的非极性化合物，但其遗传消除特异性地影响内质网（ER）中的脂肪酸去饱和，表明与ER驻留酶的直接相互作用。为了在功能上探测这种相互作用，我们开发了transorganellar互补，其中在一个细胞器中的突变途径活动进行实验测试，通过活性酶重定向到伴侣细胞器的底物可及性和互补。突变破坏三个质体驻留活动生育酚和类胡萝卜素的合成补充ER以这种方式，证明transorganellar访问至少7个非极性，质体色素定位底物从内腔的ER，可能通过质体：ER膜相互作用域。酶在任一细胞器中访问共享的非极性质体代谢物池的能力重新定义了我们对ER和叶绿体的生化连续性的理解，这对植物中合成非极性代谢物的跨细胞器途径的整合和调节具有深远的影响。
Tocopherols are nonpolar compounds synthesized and localized in plastids but whose genetic elimination specifically impacts fatty acid desaturation in the endoplasmic reticulum (ER), suggesting a direct interaction with ER-resident enzymes. To functionally probe for such interactions, we developed transorganellar complementation, where mutated pathway activities in one organelle are experimentally tested for substrate accessibility and complementation by active enzymes retargeted to a companion organelle. Mutations disrupting three plastid-resident activities in tocopherol and carotenoid synthesis were complemented from the ER in this fashion, demonstrating transorganellar access to at least seven nonpolar, plastid envelope-localized substrates from the lumen of the ER, likely through plastid:ER membrane interaction domains. The ability of enzymes in either organelle to access shared, nonpolar plastid metabolite pools redefines our understanding of the biochemical continuity of the ER and chloroplast with profound implications for the integration and regulation of organelle-spanning pathways that synthesize nonpolar metabolites in plants.