Experimental manipulation of desmosome structure

Abstract

A systematic investigation of the effects of proteolytic enzymes, chelators and detergents on desmosomes originating in a variety of tissues was undertaken. Although junctions from different tissues are morphologically similar, we found great differences in their sensitivity to various reagents, indicating dissimilarities in biochemical composition. In general, desmosomes from stratified squamous and glandular epithelia were insensitive to ethylenediaminetetraacetic acid (EDTA), but readily dissociable with trypsin. Enzymatic digestion caused disruption of material within the junctional extracellular space, and dislocation of paired desmosomal plaques. In contrast, the extracellular components of desmosomes from simple columnar epithelia were usually EDTA‐sensitive but trypsin‐resistant. There were, however, exceptions to the general pattern. Desmosomes from rat pancreas were affected only by the detergent sodium desoxycholate (DOC). DOC also solubilized the intermediate dense line of desmosomes from the frog skin. We have divided desmosomes into two broad categories based upon the differential effects of these reagents. One group, sensitive to trypsin or DOC, may be functionally “stable” in maintaining cell‐to‐cell associations for long periods. Such junctions occur in stratified squamous and many glandular epithelia. Another group of desmosomes, affected by chelating agents, may be physiologically “labile” or plastic. These junctions, occurring in simple columnar epithelia such as the gut, may respond to physiological stimuli by opening or closing, thus allowing intercellular migration of cells and substances passing through the epithelial sheet.

The α Isoform of Protein Kinase C Is Involved in Signaling the Response of Desmosomes to Wounding in Cultured Epithelial Cells

“…Borysenko and Revel (1973) showed that desmosomes in some tissues were Ca-Ind and others were disrupted by prolonged treatment with EDTA. Similar observations have been reported for colonic mucosa (Collins et al, 1990).…”

Hyper-adhesion in desmosomes: its regulation in wound healing and possible relationship to cadherin crystal structure

“…It was also shown that desmosomes in several mouse epithelial tissues are Ca 2+ independent (Wallis et al, 2000). Previously desmosomes resistant to disruption by Ca 2+ chelation have been reported in frog tissues (Borysenko and Revel, 1973).…”

Detachment of structurally intact nerve endings from chromatolytic neurones of rat superior cervical ganglion during the depression of synaptic transmission induced by post‐ganglionic axotomy.

“…The close correlation between the incidence of synapses and that of desmosomes in both normal and operated ganglia suggests that the desmosome-like attachments may be an important adjunct in the 126 MARGARET R. MATTHEWS AND VICTORIA H. NELSON mechanical stabilization of synapses; indeed, they probably function also to maintain the steric stability of the ganglion as a whole, and their loss here might well be a prerequisite of the type of retraction of dendrites described by Sumner & Watson (1971) for axotomized hypoglossal neurones. Changes in proteins at the cell surface, or possibly in ionic binding, might be the initial cause of separation of both synapses and desmosomes: Borysenko & Revel (1973) have recently shown that 'labile' classes of desmosomes may be separated by treatment with EDTA, and more 'stable' types by trypsin or desoxycholate; and Pfenninger (1971) has found that synapses, though resistant to EDTA, may be separated by solutions of high ionic strength or by proteolytic enzymes. The reappearance and coupling up of neuronal desmosomes might be an important preliminary stage in the restoration of synaptic contacts; possibly the increased incidence of neuronal attachment plaques seen in the two 9-day experiments in the present series marks a transient phenomenon of this nature.…”