Related Experiment Video
Updated: Feb 8, 2026

Photostimulation by Femtosecond Laser Activates Extracellular-signal-regulated Kinase ERK Signaling or Mitochondrial Events in Target Cells
Published on: July 6, 2019
A Switch-like Activation Relay of EGFR-ERK Signaling Regulates a Wave of Cellular Contractility for Epithelial
Yosuke Ogura1, Fu-Lai Wen2, Mustafa M Sami1
1Laboratory for Morphogenetic Signaling, RIKEN Center for Biosystems Dynamics Research, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
Abstract:
The dynamics of extracellular signal-regulated kinase (ERK) signaling underlies its versatile functions in cell differentiation, cell proliferation, and cell motility. Classical studies in Drosophila established that a gradient of epidermal growth factor receptor (EGFR)-ERK signaling is essential for these cellular responses. However, we challenge this view by the real-time monitoring of ERK activation; we show that a switch-like ERK activation is essential for the invagination movement of the Drosophila tracheal placode. This switch-like ERK activation stems from the positive feedback regulation of the EGFR-ERK signaling and a resultant relay of EGFR-ERK signaling among tracheal cells. A key transcription factor Trachealess (Trh) permissively regulates the iteration of the relay, and the ERK activation becomes graded in trh mutant. A mathematical model based on these observations and a molecular link between ERK activation dynamics and myosin shows that the relay mechanism efficiently promotes epithelial invagination while the gradient mechanism does not.
Related Concept Videos
GTPases and their Regulation
Large G-proteins,...
Directional Relays
Bacterial Signaling
The Contractile Ring
A small GTPase, RhoA, controls the function and assembly of the contractile ring. RhoA belongs to the Ras superfamily of proteins. The activation of formins by RhoA promotes...
Overcurrent Relays
Instantaneous overcurrent relays activate immediately when the input current exceeds a predetermined value, known as the pickup current, instantly energizing the circuit breaker trip coil. This rapid response is vital for addressing severe faults quickly.
Time-delay overcurrent relays, on the other...
Differential Relays

