Adhesion dynamics: mechanisms and measurements.

Adhesion to the extracellular matrix (ECM) is a fundamental requirement for survival, differentiation and migration of numerous cell types during both embryonic development and adult homeostasis. Different types of adhesion structures have been classified in different cell types or tissue environments. The best studied of these are focal adhesions which are found on a wide variety of cell types and will be the main focus of this review. Many years of research into the control of adhesion has yielded a wealth of information regarding the complexity of protein composition of these critical points of cell:ECM contact. Moreover, it has emerged that adhesions are not only highly ordered, but also dynamic structures under tight spatial control at the subcellular level to enable localised responses to extracellular cues. However, it is only in the last decade that the relative dynamics of these adhesion proteins have been closely studied. Here we provide an overview of the imaging strategies that have been developed and implemented to study the intricacies and hierarchy of protein turnover within focal adhesions. The caveats of employing these imaging techniques, as well as future directions will also be discussed.