Institute for Research in Immunology and Cancer, Université de Montréal, Montreal, Quebec, Canada.
Mol Syst Biol. 2013 May 28;9:669. doi: 10.1038/msb.2013.25.
The ERK1/2 MAP kinase pathway is an evolutionarily conserved signaling module that controls many fundamental physiological processes. Deregulated activity of ERK1/2 MAP kinases is associated with developmental syndromes and several human diseases. Despite the importance of this pathway, a comprehensive picture of the natural substrate repertoire and biochemical mechanisms regulated by ERK1/2 is still lacking. In this study, we used large-scale quantitative phosphoproteomics and bioinformatics analyses to identify novel candidate ERK1/2 substrates based on their phosphorylation signature and kinetic profiles in epithelial cells. We identified a total of 7936 phosphorylation sites within 1861 proteins, of which 155 classify as candidate ERK1/2 substrates, including 128 new targets. Candidate ERK1/2 substrates are involved in diverse cellular processes including transcriptional regulation, chromatin remodeling, RNA splicing, cytoskeleton dynamics, cellular junctions and cell signaling. Detailed characterization of one newly identified substrate, the transcriptional regulator JunB, revealed that ERK1/2 phosphorylate JunB on a serine adjacent to the DNA-binding domain, resulting in increased DNA-binding affinity and transcriptional activity. Our study expands the spectrum of cellular functions controlled by ERK1/2 kinases.
ERK1/2 MAP 激酶通路是一个进化上保守的信号模块，控制着许多基本的生理过程。ERK1/2 MAP 激酶的活性失调与发育综合征和几种人类疾病有关。尽管这条通路非常重要，但 ERK1/2 调控的天然底物谱和生化机制的全面图景仍然缺乏。在这项研究中，我们使用大规模定量磷酸化蛋白质组学和生物信息学分析，根据上皮细胞中的磷酸化特征和动力学特征，基于其磷酸化特征和动力学特征，识别出新型候选 ERK1/2 底物。我们总共在 1861 种蛋白质中鉴定出了 7936 个磷酸化位点，其中 155 个被归类为候选 ERK1/2 底物，包括 128 个新靶点。候选 ERK1/2 底物参与多种细胞过程，包括转录调控、染色质重塑、RNA 剪接、细胞骨架动态、细胞连接和细胞信号转导。对新鉴定出的转录调节因子 JunB 这一底物的详细特征分析表明，ERK1/2 在 DNA 结合域附近的丝氨酸上磷酸化 JunB，导致 DNA 结合亲和力和转录活性增加。我们的研究扩展了 ERK1/2 激酶控制的细胞功能谱。
