Galectin-3 regulates desmoglein-2 and intestinal epithelial intercellular adhesion [Cell Biology]

February 24th, 2014 by Jiang, K., Rankin, C. R., Nava, P., Sumagin, R., Kamekura, R., Stowell, S. R., Feng, M., Parkos, C. A., Nusrat, A.

The desmosomal cadherins, desmogleins and desmocollins mediate strong intercellular adhesion. Human intestinal epithelial cells express the desmoglein-2 isoform. A proteomic screen for Dsg2 associated proteins in intestinal epithelial cells identified a lectin referred to as galectin-3 (Gal3). Gal3 bound to N-linked β-galactosides in Dsg2 extracellular domain and co-sediments with caveolin-1 in lipid rafts. Down-regulation of Gal3 protein or incubation with lactose, a galactose-containing disaccharide which competitively inhibits galectin binding to Dsg2, decreased intercellular adhesion in intestinal epithelial cells. In the absence of functional Gal3, Dsg2 protein was internalized from the plasma membrane and degraded in the proteasome. These results report a novel role of Gal3 in stabilizing a desmosomal cadherin and intercellular adhesion in intestinal epithelial cells.