How Actin Polymerization and Myosin II Activity Regulate Focal Adhesion Dynamics in Motile Cells
Kovaleva A. Solomatina E. Tlegenova M. Saidova A. Vorobjev I.A.
August 2025Multidisciplinary Digital Publishing Institute (MDPI)
International Journal of Molecular Sciences
2025#26Issue 16
Focal adhesions (FAs) are multi-protein complexes that mediate cell attachment to the extracellular matrix. Their formation and maturation depend on intracellular tension generated by actin filaments interacting with phosphorylated myosin II. Using live-cell and confocal microscopy, we investigated how FA dynamics are regulated by actin polymerization and myosin II-driven contractility. We found that knockdown of myosin II resulted in complete and irreversible disassembly of FAs. However, partial inhibition of myosin II, through either ROCK or myosin light chain kinase (MLCK) inhibitors, leads to gradual FA shrinkage. In contrast, complete inhibition of myosin II phosphorylation causes disassembly of existing FAs, followed by the formation of new, small FAs at the cell periphery. In both cases, FAs formed after inhibition of myosin II phosphorylation exhibited significantly longer lifespans than FAs in control cells. Similarly, partial inhibition of actin polymerization using nanomolar concentrations of latrunculin B or cytochalasin D also promoted the formation of small FAs. Complete and irreversible FA disassembly occurred only when actin filaments were fully disrupted, leading to cell lamella retraction. These findings suggest that actin polymerization at the cell edge is the minimal and sufficient requirement for the assembly of small FAs. Notably, our data demonstrate for the first time that perturbation of the actin–myosin system results in stabilization and prolonged lifespan of small FAs, whereas larger FAs, formed in the presence of myosin II activity, are more dynamic. Together, these results emphasize the essential role of cortical actin organization and myosin II phosphorylation in the maintenance and turnover of FAs.
actin polymerization , cell adhesion , cell lamella , FA dynamics , focal adhesions (FAs) , myosin II
Text of the article Перейти на текст статьи
Department of Biology, Lomonosov Moscow State University, Moscow, 119991, Russian Federation
Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russian Federation
National Laboratory Astana, Nazarbayev University, Kabanbay Batyr Avenue 53, Astana, 010000, Kazakhstan
School of Science and Humanities, Nazarbayev University, Astana, 010000, Kazakhstan
Department of Biology
Engelhardt Institute of Molecular Biology
National Laboratory Astana
School of Science and Humanities
10 лет помогаем публиковать статьи Международный издатель
Книга Публикация научной статьи Волощук 2026 Book Publication of a scientific article 2026