Arabidopsis uses two gluconeogenic gateways for organic acids to fuel seedling establishment.
Arabidopsis uses two gluconeogenic gateways for organic acids to fuel seedling establishment.
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DOI：
10.1038/ncomms7659
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发表时间：
2015-04-10
影响因子：
16.6
通讯作者：
Hibberd, Julian M.
中科院分区：
文献类型：
--
作者：
Eastmond, Peter J.;Astley, Holly M.;Parsley, Kate;Aubry, Sylvain;Williams, Ben P.;Menard, Guillaume N.;Craddock, Christian P.;Nunes-Nesi, Adriano;Fernie, Alisdair R.;Hibberd, Julian M.
葡萄糖异生是一个基本的代谢过程，允许生物体从非碳水化合物储存如脂质和蛋白质中制造糖。在真核生物中，仅描述了一种从有机酸中间体的产酶途径，这依赖于磷酸烯醇式丙酮酸羧激酶（PCK）。在这里，我们表明，在拟南芥中存在两种途径，第二个使用丙酮酸，正磷酸二激酶（PPDK）。葡萄糖异生是关键的燃料从种子到幼苗的过渡。拟南芥pck1和ppdk突变体在种子贮藏储备动员和幼苗建立中的作用。放射性标记的研究表明，PCK主要允许糖从二羧酸，这是产品的脂质分解。然而，PPDK也允许糖由丙酮酸制成，丙酮酸是蛋白质分解的主要产物。我们认为这两种途径在植物中都是进化保守的，因为PCK消耗的能量较少，而PPDK从丙酮酸中回收碳的效率是前者的两倍。 在种子萌发过程中，植物利用异源生殖来调动非碳水化合物能量储备。Eastmond等人的研究表明，与其他真核生物不同，植物不仅依赖于通过酶PCK的促凋亡途径，而且还使用依赖于PPDK的第二种途径。
Gluconeogenesis is a fundamental metabolic process that allows organisms to make sugars from non-carbohydrate stores such as lipids and protein. In eukaryotes only one gluconeogenic route has been described from organic acid intermediates and this relies on the enzyme phosphoenolpyruvate carboxykinase (PCK). Here we show that two routes exist in Arabidopsis, and that the second uses pyruvate, orthophosphate dikinase (PPDK). Gluconeogenesis is critical to fuel the transition from seed to seedling. Arabidopsis pck1 and ppdk mutants are compromised in seed-storage reserve mobilization and seedling establishment. Radiolabelling studies show that PCK predominantly allows sugars to be made from dicarboxylic acids, which are products of lipid breakdown. However, PPDK also allows sugars to be made from pyruvate, which is a major product of protein breakdown. We propose that both routes have been evolutionarily conserved in plants because, while PCK expends less energy, PPDK is twice as efficient at recovering carbon from pyruvate. During seed germination plants use gluconeogenesis to mobilize noncarbohydrate energy reserves. Here Eastmond et al. show that plants, unlike other eukaryotes, do not solely rely on a gluconeogenic pathway via the enzyme PCK but also use a second pathway relying on PPDK.
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影响因子：
4.8
作者：
Cornah, JE;Germain, V;Smith, SM
通讯作者：
Smith, SM
影响因子：
11.6
作者：
Graham, James W. A.;Williams, Thomas C. R.;Sweetlove, Lee J.
通讯作者：
Sweetlove, Lee J.
影响因子：
56.9
作者：
Alonso, JM;Stepanova, AN;Ecker, JR
通讯作者：
Ecker, JR
影响因子：
7.4
作者：
KOBR, MJ;BEEVERS, H
通讯作者：
BEEVERS, H
DOI：
10.1073/pnas.97.10.5669
发表时间：
2000-05-09
影响因子：
11.1
作者：
Eastmond, PJ;Germain, V;Graham, IA
通讯作者：
Graham, IA