You are here: Home > Introduction > Cell Migration > Adhesion molecules
Adhesion molecules and complexes
Once the lamellipodium has formed, adhesion complexes assemble and attach it to the surface allowing the cell to generate traction. Adhesion complexes are dynamic structures and are constantly being assembled and disassembled in actively migrating cells. The precise composition of the adhesion complexes are critical for their function. For example focal adhesions are large, stable complexes composed of large numbers of proteins, and are largely composed of paxillin, vinculin and alpha-v beta-3 integrin and function to increase adhesion and therefore reduced cell migration. By contrast focal complexes are smaller multi-protein complexes, typically found at the cell front and containing less paxillin and vinculin, which are responsible for driving cell migration. An illustration of this type of adhesion complex/focal complex is shown in the image on the right.
Integrins bind to components of the extracellualr matrix such as collagen and fibronectin, attaching the cell to the substrate. The integrins are linked to the actin cytoskeleton and this interaction is stablised by the binding of proteins such as talin, tensin and vinculin. As the cell continues to move forward this complex of proteins dissociates, allowing the cell to detach from the extracellular matrix and re-attach at another point. When the cell comes to a stop the adhesion complexes can mature into more stable focal adhesions (shown below).
Website by Phil Dash