BME PhD Preliminary Exam Announcement for Donghyun Yim (T. Kim, advisor) Everyone is invited to attend the public presentation beginning at 12:00 pm. Title: Computational modeling of chemotactic cell migration enhanced with stress fiber dynamics Date: Oct 12th, 2023 Time: 12:00 pm Location: MJIS 2001 Advisory Committee: Taeyoon Kim, Chair; Adrian Buganza-Tepole; Daniel M. Suter; Qing Deng Abstract: Directional cell migration is the essential ability of many cells and occurs in the guidance of different types of cues, including substrate stiffness, surface topology, and chemoattractant gradient. In particular, when the external chemotactic stimuli are present, chemoattractant successively activates signaling pathways in the cell, followed by the nucleation and polymerization of actin filaments (F-actins). As a result, F-actin establishment and protrusion are biased at the sites with the maximal concentration of chemotactic cues, leading to migration toward chemoattractant. For the migration, formation of focal adhesions between the cell and an extracellular environment is necessary. Chemotaxis has been studied in various computational studies. However, to our knowledge, the computational model of chemotaxis considering the dynamics of F-actins and focal adhesions still lacks. To address this gap, we introduce a two-dimensional cell migration model comprising nucleus, membrane, F-actins, and underlying substrate. In this model, it is assumed that the elongation rate of an individual F-actin is enhanced by the local chemoattractant level in order to capture the dependence of the F-actin polymerization rate on the chemoattractant concentration. Repulsive forces act between F-actin and the membrane to simulate the membrane protrusion driven by elongating F-actins. F-actins are allowed to bind to substrate via focal adhesions. In preliminary results, it was observed that a cell located in the middle of a linear concentration gradient for chemoattractant protrudes and then migrates toward the region with higher concentration. We expect the current concept of the model will provide better understanding of F-actin-mediated chemotaxis.