Van Hoof Dennis, Muñoz Javier, Braam Stefan R, Pinkse Martijn W H, Linding Rune, Heck Albert J R, Mummery Christine L, Krijgsveld Jeroen
Developmental Biology and Stem Cell Research, Hubrecht Institute, Utrecht, The Netherlands.
Cell Stem Cell. 2009 Aug 7;5(2):214-26. doi: 10.1016/j.stem.2009.05.021.
Pluripotent stem cells self-renew indefinitely and possess characteristic protein-protein networks that remodel during differentiation. How this occurs is poorly understood. Using quantitative mass spectrometry, we analyzed the (phospho)proteome of human embryonic stem cells (hESCs) during differentiation induced by bone morphogenetic protein (BMP) and removal of hESC growth factors. Of 5222 proteins identified, 1399 were phosphorylated on 3067 residues. Approximately 50% of these phosphosites were regulated within 1 hr of differentiation induction, revealing a complex interplay of phosphorylation networks spanning different signaling pathways and kinase activities. Among the phosphorylated proteins was the pluripotency-associated protein SOX2, which was SUMOylated as a result of phosphorylation. Using the data to predict kinase-substrate relationships, we reconstructed the hESC kinome; CDK1/2 emerged as central in controlling self-renewal and lineage specification. The findings provide new insights into how hESCs exit the pluripotent state and present the hESC (phospho)proteome resource as a complement to existing pluripotency network databases.
多能干细胞可无限自我更新，并拥有在分化过程中重塑的特征性蛋白质-蛋白质网络。其发生机制尚不清楚。我们使用定量质谱分析法，分析了在骨形态发生蛋白（BMP）诱导分化以及去除人胚胎干细胞（hESC）生长因子过程中hESC的（磷酸化）蛋白质组。在鉴定出的5222种蛋白质中，有1399种在3067个残基上发生了磷酸化。这些磷酸化位点中约50%在分化诱导后1小时内受到调控，揭示了跨越不同信号通路和激酶活性的磷酸化网络之间的复杂相互作用。磷酸化蛋白质中有与多能性相关的蛋白质SOX2，它因磷酸化而被SUMO化。利用这些数据预测激酶-底物关系，我们重建了hESC激酶组；CDK1/2在控制自我更新和谱系特化方面成为核心。这些发现为hESC如何退出多能状态提供了新见解，并将hESC（磷酸化）蛋白质组资源作为现有多能性网络数据库的补充呈现出来。
