Review Article Focal adhesions, stress fibers and mechanical tension

Stress Fiber and Focal Adhesion are complex protein arrays that produce, transmit and sense mechanical tension. The accumulated evidence over the years has led to the conclusion that the mechanical tension generated within the stressed fibers contributes to the combination of the stress fibers themselves and the adhesion spots associated therewith. However, some recent evidence for this model has been presented. Here we support the role of mechanical tension in driving the assembly of these structures and discuss the opposite evidence. We also consider how their aggregation is affected by the stiffness of the matrix to which the cells adhere. Finally, we discuss the recent relevance between stress fiber and the nucleus and their possible role in regulating cell migration and nuclear function.

Although stress fibers play an important role in the adhesion, migration and morphogenesis of eukaryotic cells, the mechanism by which these and other contractile actin structures are produced is unknown. By analyzing the stress fiber assembly pathway using live cell microscopy, we discovered that these structures are produced by two different mechanisms. The backstressed fiber attached to the substrate by the adhesive spot at one end is assembled by actin polymerization driven by formin (mDia 1 / DRF 1) at the adhesion spot. In contrast, lateral annealing of Arp 2/3 nucleating actin bundles on myosin bundles and sheets produces lateral arcs that are not directly fixed to the substrate. It is worth noting that the stress fibers on the dorsal side and the transverse arc can be converted to the ventral stress fibers fixed at the ends of adhesions. Based on these data, we propose a general model for constructing and maintaining the structure of intracellular contractile actin.

Stress Fiber and Focal Adhesion are complex protein arrays that produce, transmit and sense mechanical tension. The accumulated evidence over the years has led to the conclusion that the mechanical tension generated within the stressed fibers contributes to the combination of the stress fibers themselves and the adhesion spots associated therewith. However, some recent evidence for this model has been presented. Here we support the role of mechanical tension in driving the assembly of these structures and discuss the opposite evidence. We also consider how their aggregation is affected by the stiffness of the matrix to which the cells adhere. Finally, we discuss the recent relevance between stress fiber and the nucleus and their possible role in regulating cell migration and nuclear function.

Both microfilaments and microtubes play a major role in mechanical transduction. In the actin cytoskeleton, mechanical transmission occurs in the intercellular ECM and intercellular adhesion by focal adhesion and adhesive bonding, respectively. The transmission of force from the outside of the cell to the inside of the cell can initiate an intracellular signaling cascade that controls the maturation or disintegration of adhesions and can alter the behavior of the cell and the cell undergoes mechanical stress It is known to assemble stress fibers. For example, cells grown on a rigid substrate will show thick stressed fibers whereas stress fibers seen in cells grown on a softer substrate will be less prominent. Mechanical forces transmitted by stress fibers to focal adhesion may also alter the conformation of mechanically sensitive adhesion proteins such as p 130 Cas and talin and contraction of the stress fibers may cause mechanical signals to be biochemically It can be converted into a signal.