• Protein abundance in cereal grains is determined by the relative rates of protein synthesis and protein degradation during grain development but quantitation of these rates is lacking.
• Through combining in vivo stable isotope labelling and in-depth quantitative proteomics, we have measured the turnover of 1400 different types of proteins during wheat grain development.
• We demonstrate that there is a spatiotemporal pattern to protein turnover rates which explain part of the variation in protein abundances that is not attributable to differences in wheat gene expression. We show that c. 20% of total grain adenosine triphosphate (ATP) production is used for grain proteome biogenesis and maintenance, and nearly half of this budget is invested exclusively in storage protein synthesis. We calculate that 25% of newly synthesized storage proteins are turned over during grain development rather than stored.
• This approach to measure protein turnover rates at proteome scale reveals how different functional categories of grain proteins accumulate, calculates the costs of protein turnover during wheat grain development and identifies the most and the least stable proteins in the developing wheat grain.

中文翻译：

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发育中的普通小麦籽粒中的蛋白质周转

• 谷物中的蛋白质丰度取决于谷物发育过程中蛋白质合成和蛋白质降解的相对速率，但缺乏对这些速率的量化。
• 通过结合体内稳定同位素标记和深入的定量蛋白质组学，我们测量了 1400 种不同类型蛋白质在小麦籽粒发育过程中的周转率。
• 我们证明了蛋白质周转率存在时空模式，这解释了蛋白质丰度的部分变化，这不是由小麦基因表达的差异引起的。我们证明了c。谷物三磷酸腺苷 (ATP) 总产量的 20% 用于谷物蛋白质组的生物发生和维持，其中近一半的预算专门用于储存蛋白质的合成。我们计算出 25% 的新合成储存蛋白在谷物发育过程中被翻转而不是储存。
• 这种在蛋白质组规模上测量蛋白质周转率的方法揭示了不同功能类别的谷物蛋白质如何积累，计算小麦籽粒发育过程中蛋白质周转的成本，并确定发育中的小麦籽粒中最稳定和最不稳定的蛋白质。