Li Lei, Nelson Clark J, Trösch Josua, Castleden Ian, Huang Shaobai, Millar A Harvey
ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009, Western Australia, Australia.
ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley 6009, Western Australia, Australia
Plant Cell. 2017 Feb;29(2):207-228. doi: 10.1105/tpc.16.00768. Epub 2017 Jan 30.
We applied N labeling approaches to leaves of the rosette to characterize their protein degradation rate and understand its determinants. The progressive labeling of new peptides with N and measuring the decrease in the abundance of >60,000 existing peptides over time allowed us to define the degradation rate of 1228 proteins in vivo. We show that Arabidopsis protein half-lives vary from several hours to several months based on the exponential constant of the decay rate for each protein. This rate was calculated from the relative isotope abundance of each peptide and the fold change in protein abundance during growth. Protein complex membership and specific protein domains were found to be strong predictors of degradation rate, while N-end amino acid, hydrophobicity, or aggregation propensity of proteins were not. We discovered rapidly degrading subunits in a variety of protein complexes in plastids and identified the set of plant proteins whose degradation rate changed in different leaves of the rosette and correlated with leaf growth rate. From this information, we have calculated the protein turnover energy costs in different leaves and their key determinants within the proteome.
我们将N标记方法应用于莲座叶，以表征其蛋白质降解速率并了解其决定因素。用N对新肽进行逐步标记，并测量60000多种现有肽随时间的丰度下降情况，使我们能够在体内定义1228种蛋白质的降解速率。我们发现，根据每种蛋白质降解率的指数常数，拟南芥蛋白质的半衰期从几小时到几个月不等。该速率是根据每种肽的相对同位素丰度以及生长过程中蛋白质丰度的倍数变化计算得出的。蛋白质复合物成员和特定蛋白质结构域是降解速率的强预测指标，而蛋白质的N端氨基酸、疏水性或聚集倾向则不是。我们在质体中的多种蛋白质复合物中发现了快速降解的亚基，并确定了一组植物蛋白质，其降解速率在莲座叶的不同叶片中发生变化，且与叶片生长速率相关。根据这些信息，我们计算了不同叶片中的蛋白质周转能量成本及其在蛋白质组中的关键决定因素。
