Delineating desmoglein adhesive properties on living keratinocytes by atomic force microscopy (60.2)

Abstract

We used atomic force microscopy (AFM) to simultaneously visualize the topography of living human keratinocytes and the distribution of the Ca2+ dependent adhesion molecule desmoglein 3 (Dsg3) in the cell membrane. Adhesion events were detectable in clusters on the cell surface and at areas of cell‐cell contact. These events were blocked by removing Ca2+ and by addition of Dsg3‐specific autoantibodies. On the cell surface, the binding forces of Dsg3 molecules were lower compared to areas of cell‐cell contact (37±2pN vs. 45±2pN), indicating that Dsg adhesive properties are not uniform but can be modulated depending on the localization. We further studied morphologic changes induced by autoantibodies targeting Dsg derived from patients with the disease pemphigus vulgaris. Autoantibody incubation resulted in separation of plasma membranes between desmosomal adhesive complexes and caused retraction of intermediate filaments, the latter of which are detectable as bundles of fiber‐like structures attached to desmosomes in the topography image. These data are in line with well‐established morphological changes induced by pemphigus autoantibodies such as interdesmosomal widening and collapse of the keratin filament cytoskeleton. Taken together, the combination of topographical and functional AFM imaging on living cells represents a powerful tool for research of cell adhesion receptors.