Figure 5. Schematic summary of major concepts.

Actin cytoskeleton dynamics are regulated by forces (blue arrows). They are also regulated by GTPases, contributing an important framework for biochemical signal transduction (red arrows). Force regulates actin dynamics by a catch-slip mechanism (yellow circle); and this biophysical regulation is modulated by biochemical signaling through RhoA and formin (gray dashed arrows). RhoA-formin module can serve as a switch shifting the force dependence of actin dynamics between catch bond (with inactivated RhoA or formin) and slip bond (with activated RhoA and formin). It may contribute a crosstalk between mechanotransduction and signal transduction pathways, which control various cell functions.