The role of hemidesmosomes and focal contacts in the skin visualized by dual-color live cell imaging.

Live cell imaging is a powerful tool to elucidate dynamics of protein(s). Our group has concentrated on dynamics of two major cell-matrix adhesion devices, hemidesmosome and focal contact in the keratinocytes. Firstly, we observed the fate of hemidesmosome protein or focal contact protein by single-color live cell imaging in the physiological setting of keratinocytes. Both hemidesmosome proteins and focal contact proteins were highly dynamic. Next, in order to observe the interaction between hemidesmosome protein and focal contact protein, we observed the fate of these proteins at the same time by dual-color live cell imaging in physiological setting and in wound setting of keratinocytes. These hemidesmosome proteins and focal contact proteins showed individual dynamics with minimal overlap expressions in physiological settings. In sharp contrast, both proteins showed highly regulated interaction in wound setting of keratinocytes. Finally, we observed the fate of BP180 protein, which is a major target of autoimmune bullous disease, bullous pemphigoid, and component of hemidesmosome, under the existence of anti-BP180 autoantibody. In results, under such a circumstance, BP180 molecules were internalized and thus keratinocyte showed weakened adhesion to the cell matrix. Our work has elucidated dynamic aspects of cell-matrix adhesion devices under both physiological and pathological conditions.