Signaling to extracellular signal-regulated kinase from ErbB1 kinase and protein kinase C: feedback, heterogeneity, and gating.
Signaling to extracellular signal-regulated kinase from ErbB1 kinase and protein kinase C: feedback, heterogeneity, and gating.
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DOI：
10.1074/jbc.m113.455345
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发表时间：
2013-07-19
期刊：
影响因子：
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通讯作者：
McArdle CA
中科院分区：
文献类型：
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作者：
Perrett RM;Fowkes RC;Caunt CJ;Tsaneva-Atanasova K;Bowsher CG;McArdle CA
背景：目前对急性ERK信号转导的机制还知之甚少。结果：反馈影响基础和急性刺激的ERK反应，但不使信号转导动力学稳健的ERK浓度。结论：急性ERK反应动力学依赖于ERK浓度和激活机制以及反馈。重要性：ERK对瞬时刺激的反应可以通过ERK浓度来门控，并且短期激活似乎是分布性的而不是进行性的。许多细胞外信号通过Raf/MEK/ERK级联起作用，其中ERK应答的动力学、细胞间变异性和敏感性都可以影响细胞命运。在这里，我们使用自动化显微镜来探索ERK介导的负反馈对表达内源性ERK或ERK 2-GFP报告基因的细胞中这些属性的影响。我们研究了急性而不是慢性刺激与表皮生长因子（ErbB 1激活）或佛波醇12，13-二丁酸酯（PKC激活）。在未受刺激的细胞中，ERK介导的负反馈降低了激活的ppERK水平的群体平均值和细胞间变异性，并增加了其对ERK表达变化的鲁棒性。在刺激的细胞中，负反馈（5分钟和4小时之间明显）也降低了磷酸化ERK（ppERK）的平均水平和变异性，而不改变反应的“等级”或敏感性。Binning细胞根据总ERK表达揭示，引人注目的是，最大ppERK反应最初发生在次最大ERK水平，这种非单调的关系变化到一个不断增加的，单调的15分钟内。这些现象发生在HeLa细胞和MCF 7乳腺癌细胞和ERK介导的负反馈的存在和不存在。他们最好的模型假设分布（而不是过程）激活。因此，我们发现了一种新的，时间依赖性的变化，在总ERK和ppERK水平之间的关系，持续没有负反馈。这种变化使得急性反应动力学依赖于ERK水平，并提供了一种“门控”或控制机制，其中刺激持续时间和ERK表达在细胞中的分布之间的相互作用可以调节对刺激有反应的细胞的比例。
Background: The mechanisms underlying acute ERK signaling are poorly understood. Results: Feedback influences basal and acutely stimulated ERK responses but does not render signaling kinetics robust to ERK concentration. Conclusion: Acute ERK response kinetics depend on ERK concentration and activation mechanism as well as feedback. Significance: ERK responses to transient stimulation can be gated by ERK concentration, and short-term activation appears distributive rather than processive. Many extracellular signals act via the Raf/MEK/ERK cascade in which kinetics, cell-cell variability, and sensitivity of the ERK response can all influence cell fate. Here we used automated microscopy to explore the effects of ERK-mediated negative feedback on these attributes in cells expressing endogenous ERK or ERK2-GFP reporters. We studied acute rather than chronic stimulation with either epidermal growth factor (ErbB1 activation) or phorbol 12,13-dibutyrate (PKC activation). In unstimulated cells, ERK-mediated negative feedback reduced the population-average and cell-cell variability of the level of activated ppERK and increased its robustness to changes in ERK expression. In stimulated cells, negative feedback (evident between 5 min and 4 h) also reduced average levels and variability of phosphorylated ERK (ppERK) without altering the “gradedness” or sensitivity of the response. Binning cells according to total ERK expression revealed, strikingly, that maximal ppERK responses initially occur at submaximal ERK levels and that this non-monotonic relationship changes to an increasing, monotonic one within 15 min. These phenomena occur in HeLa cells and MCF7 breast cancer cells and in the presence and absence of ERK-mediated negative feedback. They were best modeled assuming distributive (rather than processive) activation. Thus, we have uncovered a novel, time-dependent change in the relationship between total ERK and ppERK levels that persists without negative feedback. This change makes acute response kinetics dependent on ERK level and provides a “gating” or control mechanism in which the interplay between stimulus duration and the distribution of ERK expression across cells could modulate the proportion of cells that respond to stimulation.