Matrix mechanics and receptor–ligand interactions in cell adhesion

Cell adhesions to both soluble and insoluble extracellular matrix ligands are critical in inter and intra-cellular signaling that mediates numerous physiological processes. These adhesions are complex structures composed of many scaffolding and signaling proteins. There are four distinct types of cell–matrix adhesions: focal complexes, focal adhesions, fibrillar adhesions, and 3D cell–matrix adhesions, which vary in composition, organization and function. The primary mediators of cell–matrix adhesions are integrins, which are mechanosensitive transmembrane receptor proteins that directly bind to matrix ligands to initiate adhesion formation. The development of cell–matrix adhesions is affected by a number of factors including matrix properties such as dimensionality and rigidity, and forces, both internally and externally generated, exerted on the adhesion sites. In this article, we discuss how matrix mechanics and forces affect the assembly and maturation of cell–matrix adhesions.