Cell crawling involves intracellular actin cytoskeleton flows driven by actin polymerization at the front and myosin contractility at the back. Optogenetics allows spatial control of contraction and potentially cell migration. This study uses a one-dimensional active gel model to analyze this, incorporating myosin II minifilament assembly. The model predicts bistability between sessile and motile states under sufficient adhesion and contractility balance. Optogenetic contractility activation or inhibition can switch between these states at realistic parameter values, consistent with neutrophil experiments in microchannels. The study predicts activation strengths, initiation times, and compares local and global myosin II increases, showing that actin polymerization alone affects directional switching only at high strengths.

Oliver M. Drozdowski, Falko Ziebert, Ulrich S. Schwarz