Immunochemical analysis of the distribution of the desmosomal protein desmoglein I in different layers of plantar epidermis.

An antiserum raised against the bovine desmosomal protein desmoglein I (DGI), Mr approximately 160 kDa, was used in an immunochemical analysis of human plantar epidermis. Different layers of the tissue were prepared by means of horizontal freeze sectioning. Loosely attached surface layers were obtained by means of scraping of the skin surface with a scalpel. Tissue extracts were analysed by means of sodium dodecylsulphate polyacrylamide gel electrophoresis followed by immunoblotting. Significant amounts of a component with Mr approximately 160 kDa, reactive with the DG I-antiserum, were found in all layers except the loosely attached surface layers. In these layers the antiserum detected a component with Mr approximately 80 kDa, not found in other layers. This component may be a degradation product of DG I. Since DG I belongs to the group of transmembrane desmosomal proteins that is believed to constitute the link between the intracellular parts of desmosomes of opposing cells, it is concluded that desmosomes may play an important role in plantar stratum corneum cell cohesion, and that degradation of desmosomes may be an important step in desquamation in plantar epidermis.