Actin cytoskeleton protection by the formin-mediated safety valve

Mechanical forces shape cellular form and function by regulating key cellular processes; however, when dysregulated, they contribute to disease. Excessive forces can be detrimental to cells, damaging cytoskeleton, deforming nuclei, and even rupturing the cell itself. To counteract these effects, cells deploy protective mechanisms that enhance mechanical resilience. Emerging evidence highlights a novel strategy for rapid tension release via force-dependent actin polymerization mediated by formin-family proteins such as Dia1. Acting as a mechanical "safety valve", Dia1 buffers otherwise damaging stress and promotes zyxin-mediated repair, preserving cytoskeletal architecture, safeguarding the nucleus, and maintaining cellular integrity. Loss of Dia1 disrupts signaling cascades that converge on key mechanotransduction processes governing cell fate and disease progression. In this review, we explore recent advances in force-dependent actin polymerization and its role in cytoskeletal protection, nuclear homeostasis, and cellular adaptation to mechanical forces.