Institute of Cell Biology, University of Bern, Bern, Switzerland.
Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland.
Mol Syst Biol. 2022 Jun;18(6):e10670. doi: 10.15252/msb.202110670.
Combining single-cell measurements of ERK activity dynamics with perturbations provides insights into the MAPK network topology. We built circuits consisting of an optogenetic actuator to activate MAPK signaling and an ERK biosensor to measure single-cell ERK dynamics. This allowed us to conduct RNAi screens to investigate the role of 50 MAPK proteins in ERK dynamics. We found that the MAPK network is robust against most node perturbations. We observed that the ERK-RAF and the ERK-RSK2-SOS negative feedback operate simultaneously to regulate ERK dynamics. Bypassing the RSK2-mediated feedback, either by direct optogenetic activation of RAS, or by RSK2 perturbation, sensitized ERK dynamics to further perturbations. Similarly, targeting this feedback in a human ErbB2-dependent oncogenic signaling model increased the efficiency of a MEK inhibitor. The RSK2-mediated feedback is thus important for the ability of the MAPK network to produce consistent ERK outputs, and its perturbation can enhance the efficiency of MAPK inhibitors.
将 ERK 活性动力学的单细胞测量与扰动相结合，可深入了解 MAPK 网络拓扑结构。我们构建了由光遗传学激活子激活 MAPK 信号和 ERK 生物传感器测量单细胞 ERK 动力学的电路。这使我们能够进行 RNAi 筛选，以研究 50 种 MAPK 蛋白在 ERK 动力学中的作用。我们发现 MAPK 网络对大多数节点扰动具有鲁棒性。我们观察到 ERK-RAF 和 ERK-RSK2-SOS 负反馈同时运作，以调节 ERK 动力学。绕过 RSK2 介导的反馈，无论是通过直接光遗传学激活 RAS，还是通过 RSK2 扰动，都使 ERK 动力学对进一步的扰动更加敏感。类似地，在人类 ErbB2 依赖性致癌信号模型中靶向该反馈，可提高 MEK 抑制剂的效率。因此，RSK2 介导的反馈对于 MAPK 网络产生一致的 ERK 输出的能力很重要，其扰动可提高 MAPK 抑制剂的效率。
