This traction can be visualized with traction force microscopy. A common metaphor to explain actin retrograde flow is a large number of people being washed downriver, and as they do so, some of them hang on to rocks and branches along the bank to stop their downriver motion. Thus, a pulling force is generated onto the rock or branch that they are hanging on to. These forces are necessary for the successful assembly, growth, and maturation of focal adhesions. Natural biomechanical sensor Extracellular mechanical forces, which are exerted through focal adhesions, can activate Src kinase and stimulate the growth of the adhesions. This indicates that focal adhesions may function as mechanical sensors, and suggests that force generated from myosin fibers could contribute to maturing the focal complexes. This gains further support from the fact that inhibition of myosin-generated forces leads to slow disassembly of focal adhesions, by changing the turnover kinetics of the focal adhesion proteins. The relationship between forces on focal adhesions and their compositional maturation, however, remains unclear. For instance, preventing focal adhesion maturation by inhibiting myosin activity or stress fiber assembly does not prevent forces sustained by focal adhesions, nor does it prevent cells from migrating. Thus force propagation through focal adhesions may not be sensed directly by cells at all time and force scales. Their role in mechanosensing is important for durotaxis. See also Actin TES (protein) Paxillin References External links MBInfo - Focal Adhesion MBInfo - Focal Adhesion Assembly MBInfo - Regulation of Focal Adhesion Assembly AdhesomeFAnetwork Database with all known focal adhesion proteins and their biochemical interactions Intercellular Connections Zaidel-Bar Cell Adhesion Lab Cell biology Cell movement Cell signaling Actin-based structures