Journal of Biological Chemistry
Volume 277, Issue 7, 15 February 2002, Pages 5024-5029
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MOLECULAR BASIS OF CELL AND DEVELOPMENTAL BIOLOGY
Corneodesmosin, a Component of Epidermal Corneocyte Desmosomes, Displays Homophilic Adhesive Properties*

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Corneodesmosomes, the modified desmosomes of the uppermost layers of the epidermis, play an important role in corneocyte cohesion. Corneodesmosin is a secreted glycoprotein located in the corneodesmosomal core and covalently linked to the cornified envelope of corneocytes. Its glycine- and serine-rich NH2-terminal domain may fold to give structural motifs similar to the glycine loops described in epidermal cytokeratins and loricrin and proposed to display adhesive properties. A chimeric protein comprising human corneodesmosin linked to the transmembrane and cytoplasmic domains of mouse E-cadherin was expressed in mouse fibroblasts to test the ability of corneodesmosin to promote cell-cell adhesion. Classic aggregation assays indicated that corneodesmosin mediates homophilic cell aggregation. Moreover, Ca2+depletion showed a moderate effect on aggregation. To assess the involvement of the glycine loop domain in adhesion, full-length corneodesmosin, corneodesmosin lacking this domain, or this domain alone were expressed as glutathione S-transferase fusion proteins and tested for protein-protein interactions by overlay binding assays. The results confirmed that corneodesmosin presents homophilic interactions and indicated that its NH2-terminal glycine loop domain is sufficient but not strictly necessary to promote binding. Altogether, these results provide the first experimental evidence for the adhesive properties of corneodesmosin and for the involvement of its glycine loop domain in adhesion.

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Published, JBC Papers in Press, December 5, 2001, DOI 10.1074/jbc.M108438200

*

This study was supported in part by grants from the Université Paul Sabatier-Toulouse III (JE 1965 DGRT), from the Société de Recherche Dermatologique, from the Region Midi-Pyrénées, and from INSERM (CJF 9602).The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

Supported by a post-doctoral fellowship from the Société de Secours des Amis des Sciences and from the Fondation Singer Polignac.

§

A recipient of a scholarship from the French Ministry of Research and Technology.