Cell signaling networks coordinate specific patterns of protein expression in response to external cues, yet the logic by which signaling pathway activity determines the eventual abundance of target proteins is complex and poorly understood. Here, we describe an approach for simultaneously controlling the Ras/Erk pathway and monitoring a target gene’s transcription and protein accumulation in single live cells. We apply our approach to dissect how Erk activity is decoded by immediate early genes (IEGs). We find that IEG transcription decodes Erk dynamics through a shared band-pass filtering circuit; repeated Erk pulses transcribe IEGs more efficiently than sustained Erk inputs. However, despite highly similar transcriptional responses, each IEG exhibits dramatically different protein-level accumulation, demonstrating a high degree of post-transcriptional regulation by combinations of multiple pathways. Our results demonstrate that the Ras/Erk pathway is decoded by both dynamic filters and logic gates to shape target gene responses in a context-specific manner.

细胞信号网络协调特定的蛋白质表达模式以响应外部线索，但信号通路活性决定靶蛋白最终丰度的逻辑是复杂的，并且知之甚少。在这里，我们描述了一种同时控制 Ras/Erk 通路和监测靶基因在单个活细胞中的转录和蛋白质积累的方法。我们应用我们的方法来剖析 Erk 活动如何被直接早期基因 (IEG) 解码。我们发现 IEG 转录通过共享带通滤波电路解码 Erk 动力学；重复的 Erk 脉冲比持续的 Erk 输入更有效地转录 IEG。然而，尽管转录反应非常相似，但每个 IEG 表现出显着不同的蛋白质水平积累，通过多种途径的组合证明了高度的转录后调节。我们的结果表明，Ras/Erk 通路由动态过滤器和逻辑门解码，以特定于上下文的方式塑造目标基因反应。