Proteomics Unit, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
The Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark.
Nat Commun. 2021 Mar 25;12(1):1863. doi: 10.1038/s41467-021-22181-5.
Embryonic stem cells (ESCs) can be maintained in the naïve state through inhibition of Mek1/2 and Gsk3 (2i). A relevant effect of 2i is the inhibition of Cdk8/19, which are negative regulators of the Mediator complex, responsible for the activity of enhancers. Inhibition of Cdk8/19 (Cdk8/19i) stimulates enhancers and, similar to 2i, stabilizes ESCs in the naïve state. Here, we use mass spectrometry to describe the molecular events (phosphoproteome, proteome, and metabolome) triggered by 2i and Cdk8/19i on ESCs. Our data reveal widespread commonalities between these two treatments, suggesting overlapping processes. We find that post-transcriptional de-repression by both 2i and Cdk8/19i might support the mitochondrial capacity of naive cells. However, proteome reprogramming in each treatment is achieved by different mechanisms. Cdk8/19i acts directly on the transcriptional machinery, activating key identity genes to promote the naïve program. In contrast, 2i stabilizes the naïve circuitry through, in part, de-phosphorylation of downstream transcriptional effectors.
胚胎干细胞（ESCs）可以通过抑制 Mek1/2 和 Gsk3（2i）来维持在原始状态。2i 的一个相关作用是抑制 Cdk8/19，Cdk8/19 是中介复合物的负调节剂，负责增强子的活性。抑制 Cdk8/19（Cdk8/19i）会刺激增强子，并与 2i 类似，使 ESCs 稳定在原始状态。在这里，我们使用质谱法描述了 2i 和 Cdk8/19i 在 ESCs 上引发的分子事件（磷酸化组、蛋白质组和代谢组）。我们的数据揭示了这两种处理之间广泛的共同性，表明存在重叠的过程。我们发现，2i 和 Cdk8/19i 的转录后去抑制可能支持原始细胞的线粒体能力。然而，每种处理中的蛋白质组重编程是通过不同的机制实现的。Cdk8/19i 直接作用于转录机制，激活关键的身份基因，以促进原始程序。相比之下，2i 通过部分去磷酸化下游转录效应物来稳定原始电路。
