Ethological dynamics in diorama environments

During the amoeboid locomotion of fish epidermal keratocytes, multiple arrays of stress fibers, arranged just along the seams of a rugby ball in the cell body, rotate like a wheel. The role of the wheel in a typical locomotor is to generate propulsive force and control the direction of movement. The goal of this study is to determine whether the stress fibers act as wheels and are responsible for propulsion or directional control. In most amoeboid cells, including keratocytes, pseudopodia are elongated by actin polymerization. In this study, we hypothesize and demonstrate that pseudopodia elongation is responsible for propulsion and stress fiber rotation is responsible for directional control. Because stress fibers are composed of actin filaments, there has been no way to inhibit only pseudopod elongation by actin polymerization without affecting stress fiber rotation. Recently, we have found a method to stop pseudopod elongation alone. We combine this method with biophysical methods such as 3D observation of stress fiber dynamics, measurement of substrate traction forces and mechanical modeling to prove our hypothesis. This research aims to elucidate the kinetics of the intracellular machinery "stress fibers", and its success could be applied to biomimetic mobiles.