Department Biology I, Plant Evolutionary Cell Biology, Ludwig-Maximilians-Universität München, Planegg-Martinsried, Germany.
Department of Ecogenomics and Systems Biology, University of Vienna, Vienna, Austria.
Plant J. 2019 Nov;100(3):438-455. doi: 10.1111/tpj.14472. Epub 2019 Sep 25.
Plant cells are characterized by a high degree of compartmentalization and a diverse proteome and metabolome. Only a very limited number of studies has addressed combined subcellular proteomics and metabolomics which strongly limits biochemical and physiological interpretation of large-scale 'omics data. Our study presents a methodological combination of nonaqueous fractionation, shotgun proteomics, enzyme activities and metabolomics to reveal subcellular diurnal dynamics of plant metabolism. Subcellular marker protein sets were identified and enzymatically validated to resolve metabolism in a four-compartment model comprising chloroplasts, cytosol, vacuole and mitochondria. These marker sets are now available for future studies that aim to monitor subcellular metabolome and proteome dynamics. Comparing subcellular dynamics in wild type plants and HXK1-deficient gin2-1 mutants revealed a strong impact of HXK1 activity on metabolome dynamics in multiple compartments. Glucose accumulation in the cytosol of gin2-1 was accompanied by diminished vacuolar glucose levels. Subcellular dynamics of pyruvate, succinate and fumarate amounts were significantly affected in gin2-1 and coincided with differential mitochondrial proteome dynamics. Lowered mitochondrial glycine and serine amounts in gin2-1 together with reduced abundance of photorespiratory proteins indicated an effect of the gin2-1 mutation on photorespiratory capacity. Our findings highlight the necessity to resolve plant metabolism to a subcellular level to provide a causal relationship between metabolites, proteins and metabolic pathway regulation.
植物细胞的特点是高度分隔和多样化的蛋白质组和代谢组。只有极少数研究涉及联合亚细胞蛋白质组学和代谢组学,这极大地限制了对大规模“组学”数据的生化和生理解释。我们的研究提出了一种非水部分分离、鸟枪法蛋白质组学、酶活性和代谢组学的方法组合,以揭示植物代谢的亚细胞日动态。确定了亚细胞标记蛋白组,并通过酶学验证来解析由叶绿体、细胞质、液泡和线粒体组成的四室模型中的代谢。这些标记物集现在可用于未来的研究,旨在监测亚细胞代谢组和蛋白质组动态。比较野生型植物和 HXK1 缺陷 gin2-1 突变体的亚细胞动力学,发现 HXK1 活性对多个隔室的代谢物动力学有很强的影响。gin2-1 中细胞质中葡萄糖的积累伴随着液泡中葡萄糖水平的降低。gin2-1 中丙酮酸、琥珀酸和富马酸的亚细胞动力学显著受到影响,与线粒体蛋白质组动力学的差异相一致。gin2-1 中降低的线粒体甘氨酸和丝氨酸含量以及减少的光呼吸蛋白丰度表明 gin2-1 突变对光呼吸能力的影响。我们的研究结果强调了将植物代谢解析到亚细胞水平的必要性,以提供代谢物、蛋白质和代谢途径调节之间的因果关系。