ARC Centre of Excellence in Plant Energy Biology, Perth, WA, Australia.
Western Australian Proteomics, The University Western Australia, Perth, WA, Australia.
Plant J. 2022 Feb;109(4):745-763. doi: 10.1111/tpj.15661. Epub 2022 Feb 12.
Plants have a diurnal separation of metabolic fluxes and a need for differential maintenance of protein machinery in the day and night. To directly assess the output of the translation process and to estimate the ATP investment involved, the individual rates of protein synthesis and degradation of hundreds of different proteins need to be measured simultaneously. We quantified protein synthesis and degradation through pulse labelling with heavy hydrogen in Arabidopsis thaliana rosettes to allow such an assessment of ATP investment in leaf proteome homeostasis on a gene-by-gene basis. Light-harvesting complex proteins were synthesised and degraded much faster in the day (approximately 10:1), while carbon metabolism and vesicle trafficking components were translated at similar rates day or night. Few leaf proteins changed in abundance between the day and the night despite reduced protein synthesis rates at night, indicating that protein degradation rates are tightly coordinated. The data reveal how the pausing of photosystem synthesis and degradation at night allows the redirection of a decreased energy budget to a selective night-time maintenance schedule.
植物具有代谢通量的昼夜分离，并且需要在白天和黑夜对蛋白质机器进行差异化的维护。为了直接评估翻译过程的输出，并估计所涉及的 ATP 投资，需要同时测量数百种不同蛋白质的合成和降解的个体速率。我们通过在拟南芥莲座叶中用重氢进行脉冲标记来量化蛋白质的合成和降解，从而能够在基因水平上评估叶片蛋白质组动态平衡中的 ATP 投资。在白天，光捕获复合物蛋白的合成和降解速度要快得多（大约为 10:1），而碳代谢和囊泡运输成分的翻译速度在白天和晚上相似。尽管夜间蛋白质合成率降低，但仍有少数叶片蛋白的丰度发生变化，表明蛋白质降解率是紧密协调的。这些数据揭示了光合作用系统合成和降解在夜间的暂停如何允许将减少的能量预算重新定向到选择性的夜间维护计划。
