Data from: Cell-specific responses to the cytokine TGFβ are determined by variability in protein levels

The cytokine TGFβ provides important information during embryonic development, adult tissue homeostasis and regeneration. Alterations in the cellular response to TGFβ are involved in severe human diseases. To understand how cells encode the extracellular input and transmit its information to elicit appropriate responses, we acquired quantitative time-resolved measurements of pathway activation at the single cell level. We established dynamic time warping to quantitatively compare signaling dynamics of thousands of individual cells and described heterogeneous single-cell responses by mathematical modeling. Our combined experimental and theoretical study revealed that the response to a given dose of TGFβ is determined cell-specifically by the levels of defined signaling proteins. This heterogeneity in signaling protein expression leads to decomposition of cells into classes with qualitatively distinct signaling dynamics and phenotypic outcome. Negative feedback regulators promote heterogeneous signaling, as a SMAD7 knock-out specifically affected the signal duration in a subpopulation of cells. Taken together, we propose a quantitative framework that allows predicting and testing sources of cellular signaling heterogeneity.

细胞因子转化生长因子β（TGFβ）可在胚胎发育、成年组织稳态维持及再生过程中传递关键信号。细胞对TGFβ应答的异常改变与多种人类重症疾病密切相关。为阐明细胞如何编码胞外信号并传递其信息以触发恰当应答，我们开展了单细胞水平下通路激活的定量时间分辨检测。我们建立了动态时间规整（dynamic time warping）方法，以定量对比数千个单个细胞的信号转导动态，并通过数学建模刻画了异质性单细胞应答的特征。本项实验与理论联合研究显示，细胞对特定剂量TGFβ的应答，由特定信号蛋白的表达水平以细胞特异性方式决定。信号蛋白表达的这种异质性，使得细胞被划分为多组具有截然不同信号转导动态与表型结局的细胞类群。负反馈调控因子可加剧信号转导的异质性：SMAD7基因敲除会特异性影响部分细胞亚群的信号持续时长。综上，我们提出了一套定量分析框架，可用于预测并验证细胞信号转导异质性的来源。