Actin arch formation induced by matrix deformability

Actin stress fibers are crucial determinants of cellular adhesion morphology, and their structural formation depends on the mechanical properties of the extracellular microenvironment. This study aims to expand on the established understanding of two-dimensional actin arcs by uncovering the mechanisms driving the formation of threedimensional actin arcs on deformable substrates. Specifically, we evaluated how the viscoelasticity of the extracellular matrix influences the three-dimensional dynamics of actin stress fibers. Using PNIPAAm-grafted substrates with varying polymer chain lengths, we observed that longer chains with higher deformability and energy dissipation promoted the formation of three-dimensional actin arcs. Furthermore, we examined the impact of substrate energy dissipation on the central angle of actin arcs, revealing that matrix viscoelasticity plays a significant role in regulating the threedimensional behavior of actin stress fibers. These findings highlight the critical role of matrix viscoelasticity in modulating the three-dimensional dynamics of actin stress fibers.