The new basement membrane antigen recognized by the monoclonal antibody GB3 is a large size glycoprotein: modulation of its expression by retinoic acid.

Abstract

Further biochemical investigations on the hemidesmosome-associated epidermal basement membrane component recognized by the monoclonal antibody GB3 are presented in this study. We previously found that the expression of this constituent is impaired in a severe genodermatosis termed lethal junctional epidermolysis bullosa. We demonstrate now that this factor is a very large glycoprotein (apparent molecular weight, 600 kDa) made up of polypeptides in the range of 93.5 to 150 kDa, and containing N-linked oligosaccharide chains. Both endo-beta-N-acetylglucosaminidases and neuraminidase hydrolysis, as well as concanavalin A binding experiments were performed on the GB3 radioimmunoprecipitated polypeptides from cultured human keratinocytes. They showed that the antigen subunits probably bear both 'high-mannose' and 'complex' type glycosidic chains. The chronic exposure of cultured human keratinocytes to retinoic acid (10(-8) to 10(-6) M) resulted in no apparent changes in the overall bulk of these glycosidic chains, but a dose-dependent increase of synthesis and secretion of the antigen was observed. A relative induction factor of 4 was obtained in cultures treated with 10(-6) M retinoic acid. This induction was also observed morphologically by indirect immunofluorescence at the basement membrane zone from cultured human keratinocytes grown on dead de-epidermized dermis. These results further emphasize the influence of glycoproteins in cell-cell and cell-substratum attachment. Furthermore, the ability to modulate this antigen may be relevant for the understanding of the molecular defect involved in lethal junctional epidermolysis bullosa.

• Authors: P Verrando, A Pisani, J P Ortonne
• Journal: Biochimica et biophysica acta (Biochim Biophys Acta) Vol. 942 Issue 1 Pg. 45-56 (Jul 07 1988) ISSN: 0006-3002 [Print] Netherlands
• PMID: 2454667 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antibodies, Monoclonal
• Epitopes
• Macromolecular Substances
• Membrane Glycoproteins
• Concanavalin A
• Tunicamycin
• Tretinoin
• Glycoside Hydrolases

Topics

• Antibodies, Monoclonal (immunology)
• Basement Membrane (immunology)
• Cells, Cultured
• Concanavalin A (metabolism)
• Desmosomes (immunology)
• Epitopes
• Fluorescent Antibody Technique
• Glycoside Hydrolases (metabolism)
• Humans
• Immunologic Techniques
• Macromolecular Substances
• Membrane Glycoproteins (immunology)
• Molecular Weight
• Oxidation-Reduction
• Tretinoin (pharmacology)
• Tunicamycin (pharmacology)