Interactions between biological surfaces

Cell adhesion is essentially mediated by the interplay of specific receptors. Although many experiments were performed to measure the force required to rupture individual bonds, only recent theoretical work has allowed a correct interpretation of reported data. The biological relevance of these studies is enhanced by the demonstration of a quantitative connection between the mechanical strength of cell-to-substrate adhesion and migration velocity. Furthermore, a new experimental approach has opened the way to a quantitative study of the relationship between cell adhesion and the behavior of specific receptors by simultaneous monitoring of cell spreading, adhesive strength, and receptor redistribution. Elegant applications of genetic engineering have shed new light on the relationship between receptor structure and functions; thus, the physiological importance of Cadherin microaggregation has been demonstrated and the structural basis of specificity has been illustrated by changing the specificity of integrin receptors by changing a short peptide sequence. All these examples illustrate the progress achieved in relating cell behavior to the structure and function of individual molecules.