Pablo A. Iglesias
Date: May 07, 2019. 12:00
Location: CCU Seminar Room
Title: The set point of coupled excitable systems: relations to wave propagation and morphology of protrusions in migrating cells
Affiliation: Department of Electrical & Computer Engineering, The Johns Hopkins University
The study of excitable systems, which arose from a desire to understand the behavior of neurons, has a rich theoretical history. When excitable systems exist in diffusible media, the activity of the system can propagate as a traveling wave. In the last decade, there have been numerous reports that many of the regulators of actin-polymerization in migrating cells display wave propagation consistent with the existence of an underlying excitable system. In this talk I will present a comprehensive model for cell migration that explains cell movement in terms of excitable behavior. The presence of an excitable system accounts for the spontaneous migration of unstimulated cells and the directed migration of cells guided by external cues.
I show that there are two distinct but coupled excitable systems, a signal transduction excitable network (STEN) and a cytoskeletal excitable network (CEN) which display different wave behaviors. Through theory and simulation, I show that the frequency, speed, and range of the observed waves depends on the strengths of the various feedback loops within these networks. Finally, I show that the model predicts a number of other possible dynamic behaviors based on changes of the set point in the excitable system. I demonstrate how these behaviors can be induced in live cells, and illustrate how these behaviors lead to morphologically distinct cellular protrusions.