Live Visualization of ERK Activity in the Mouse Blastocyst Reveals Lineage-Specific Signaling Dynamics

AbstractStimulation of PC-12 cells with epidermal (EGF) versus nerve (NGF) growth factors (GFs) biases the distribution between transient and sustained single-cell ERK activity states, and between proliferation and differentiation fates within a cell population. We report that fibroblast GF (FGF2) evokes a distinct behavior that consists of a gradually changing population distribution of transient/sustained ERK signaling states in response to increasing inputs in a dose response. Temporally-controlled GF perturbations of MAPK signaling dynamics applied using microfluidics reveals that this wider mix of ERK states emerges through the combination of an intracellular feedback, and competition of FGF2 binding to FGF receptors (FGFR) and heparan-sulfate proteoglycans (HSPGs) co-receptors. We show that the latter experimental modality is instructive for model selection using a Bayesian parameter inference. Our results provide novel insights into how different receptor tyrosine kinase (RTK) systems differentially wire the MAPK network to fine tune fate decisions at the cell population-level.Microfluidics, Erk Signaling Dynamics, Mechanistic Modelling, Parameter Estimation, Cell Fate Determination

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MAPK activity dynamics regulate non-cell autonomous effects of oncogene expression

eLife ◽

10.7554/elife.60541 ◽

2020 ◽

Vol 9 ◽

Author(s):

Timothy J Aikin ◽

Amy F Peterson ◽

Michael J Pokrass ◽

Helen R Clark ◽

Sergi Regot

Keyword(s):

Large Fraction ◽

Temporal Patterns ◽

Genetic Alterations ◽

Mapk Signaling ◽

Mitogen Activated Protein Kinase ◽

Oncogene Expression ◽

Mapk Activity ◽

Signaling Dynamics ◽

Mitogen Activated Protein ◽

Erk Activity

A large fraction of human cancers contain genetic alterations within the Mitogen Activated Protein Kinase (MAPK) signaling network that promote unpredictable phenotypes. Previous studies have shown that the temporal patterns of MAPK activity (i.e. signaling dynamics) differentially regulate cell behavior. However, the role of signaling dynamics in mediating the effects of cancer driving mutations has not been systematically explored. Here, we show that oncogene expression leads to either pulsatile or sustained ERK activity that correlate with opposing cellular behaviors (i.e. proliferation vs. cell cycle arrest, respectively). Moreover, sustained–but not pulsatile–ERK activity triggers ERK activity waves in unperturbed neighboring cells that depend on the membrane metalloprotease ADAM17 and EGFR activity. Interestingly, the ADAM17-EGFR signaling axis coordinates neighboring cell migration toward oncogenic cells and is required for oncogenic cell extrusion. Overall, our data suggests that the temporal patterns of MAPK activity differentially regulate cell autonomous and non-cell autonomous effects of oncogene expression.

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A Real-Time Biosensor for ERK Activity Reveals Signaling Dynamics during C. elegans Cell Fate Specification

Developmental Cell ◽

10.1016/j.devcel.2017.07.014 ◽

2017 ◽

Vol 42 (5) ◽

pp. 542-553.e4 ◽

Cited By ~ 53

Author(s):

Claire de la Cova ◽

Robert Townley ◽

Sergi Regot ◽

Iva Greenwald

Keyword(s):

Real Time ◽

Cell Fate ◽

Cell Fate Specification ◽

Fate Specification ◽

C Elegans ◽

Signaling Dynamics ◽

Erk Activity

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A synthetic gene circuit for imaging-free detection of dynamic cell signaling

10.1101/2021.01.06.425615 ◽

2021 ◽

Author(s):

Pavithran T. Ravindran ◽

Sarah McFann ◽

Jared E. Toettcher

Keyword(s):

Intracellular Signaling ◽

Fluorescent Protein ◽

Live Cell ◽

Spatiotemporal Resolution ◽

Gene Circuit ◽

Signaling Dynamics ◽

Dynamic Cell ◽

Sense And Respond ◽

Erk Activity ◽

Fluorescent Protein Reporter

AbstractCells employ intracellular signaling pathways to sense and respond to changes in their external environment. In recent years, live-cell biosensors have revealed complex pulsatile dynamics in many pathways, but studies of these signaling dynamics are limited by the necessity of live-cell imaging at high spatiotemporal resolution1. Here, we describe an approach to infer pulsatile signaling dynamics from just a single measurement in fixed cells using a pulse-detecting gene circuit. We computationally screened for circuit with pulse detecting capability, revealing an incoherent feedforward topology that robustly performs this computation. We then implemented the motif experimentally for the Erk signaling pathway using a single engineered transcription factor and fluorescent protein reporter. Our ‘recorder of Erk activity dynamics’ (READer) responds sensitively to both spontaneous and stimulus-driven Erk pulses. READer circuits thus open the door to permanently labeling transient, dynamic cell populations to elucidate the mechanistic underpinnings and biological consequences of signaling dynamics.

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