A mechanobiological feedback model for the oscillations of myosin II and cell shape in epithelia
Tianzhi Luo (Johns Hopkins School of Medici), Douglas Robinson (Johns Hopkins School of Medicine)
Mechanics and Physics of Biological Cells
Wed 9:00 - 10:30
Barus-Holley 141
Actin-myosin network is known to drive the constriction of epithelial cells in tissues and embryos, which is very important for epithelial morphogenesis. Recent experiments witness the strong correlation of myosin II localizations and cell shape oscillations in epithelia. These oscillations display different characteristics in apical and basal surfaces of the epithelia while corresponding actin-myosin network posses different microstructures. In the apical surface, myosin localizes largely to the cell-cell interface. However, it shows relatively uniform distribution in the basal surface. The oscillation frequencies of myosin in these two surfaces are also different. However, a quantitative understanding of the correlations between myosin and cell surface in multicellular structures is still lacking. Here, we present a mathematic model that includes the molecular mechanism of the force-dependent binding of myosin to actin, the viscoelastic nature of the cellular deformation, and physical interaction of neighboring cells with experimental measured values. The implementation of this model to epithelia in 2D and 3D simulations reproduces the experimental observed oscillations of myosin and cell shape in both apical and basal surfaces of flat, cylindrical, and spherical epithelia. Our model indicates that the oscillation frequency is determined by ration between the stiffness and the viscoelasticity of the cells. The maintenance of the oscillations can be either trigged by biological signals in the upstream of myosin II or just by the mechanical interactions between neighboring cells. More importantly, this model predicts a phase diagram for the oscillation occurrence in epithelia with different myosin II activities and mechanical properties.