Analysis of integrin dynamics by fluorescence recovery after photobleaching

Cell migration is a complex cellular behavior that involves the controlled reorganization of the link between the actin cytoskeleton and the extracellular matrix. This mechanical connection is provided by transmembrane receptors of the integrin family. Integrins are heterodimeric receptors that undergo an allosteric switch when activated by external or intracellular signals, providing binding sites for ligands of the extracellular matrix and actin-associated cytoplasmic adapter proteins. Techniques such as fluorescence recovery after photobleaching (FRAP) are used to analyze the remodeling of green fluorescent protein (GFP)-tagged integrin receptors within focal adhesions, demonstrating that the dynamics of the remodeling of integrins in substrate adhesion sites is carefully regulated by extracellular ligands, cytoskeletal adapter proteins, and the actin cytoskeleton. FRAP analysis of GFP-tagged integrins is a tool that allows one to detect and dissect the internal dynamics of apparently immobile focal adhesions, allowing one to perceive the hierarchies and mechanisms of focal adhesion formation and dispersion.