The study explores the relationship between mechanical force and the development of focal complexes in cells. It shows that initial integrin-ECM adhesions can exert migration force once they recruit vinculin, a marker for focal complexes. The research demonstrates that mechanical force, either applied internally or externally, can induce the formation of focal complexes. These focal complexes are crucial for cells to exert migration force, as they are formed by the recruitment of vinculin and other proteins. The study also shows that focal complexes can form on small ligand-coated surfaces when external force is applied, such as through an optical laser trap. The formation of focal complexes is dependent on the recruitment of vinculin and is influenced by the presence of c-Src, a protein that regulates the strength of adhesions. The results indicate that mechanical force is a key signal for cells to strengthen initial integrin-ECM adhesions into focal complexes and to regulate the amount of migration force applied at individual adhesions. The study highlights the importance of focal complexes in dynamic migration events and their role in the regulation of cell movement.The study explores the relationship between mechanical force and the development of focal complexes in cells. It shows that initial integrin-ECM adhesions can exert migration force once they recruit vinculin, a marker for focal complexes. The research demonstrates that mechanical force, either applied internally or externally, can induce the formation of focal complexes. These focal complexes are crucial for cells to exert migration force, as they are formed by the recruitment of vinculin and other proteins. The study also shows that focal complexes can form on small ligand-coated surfaces when external force is applied, such as through an optical laser trap. The formation of focal complexes is dependent on the recruitment of vinculin and is influenced by the presence of c-Src, a protein that regulates the strength of adhesions. The results indicate that mechanical force is a key signal for cells to strengthen initial integrin-ECM adhesions into focal complexes and to regulate the amount of migration force applied at individual adhesions. The study highlights the importance of focal complexes in dynamic migration events and their role in the regulation of cell movement.