Linear contraction of stress fibers generates cell body rotation

<h2>Summary</h2> Fish epidermal keratocytes, which rapidly repair wounds, comprise a frontal crescent-shaped lamellipodium and a rear rugby-ball-shaped cell body. The cell body rotates like a wheel during migration. Stress fibers are arranged along the seams of the rugby ball. Here, we show the linear contraction of stress fibers to be the driving force for rotation. We constructed a toy mechanical robot of the cell body that consisted of a soft cylinder with a contractile coil. From its motion, it was predicted that contraction of the stress fibers would deform the soft cell body and that the deformed cell body would push against the substrate to generate torque. This prediction was confirmed by the observation of stress fiber dynamics in migrating cells. Knowledge gained from this unique migration mechanism has the potential to be used in the design of biomimetic soft robots.