Apical sorting by galectin-3-dependent glycoprotein clustering

Summary, in English

Epithelial cells are characterized by their polarized organization based on an apical membrane that is separated from the basolateral membrane domain by tight junctions. Maintenance of this morphology is guaranteed by highly specific sorting machinery that separates lipids and proteins into different carrier populations for the apical or basolateral cell surface. Lipid-raft-independent apical carrier vesicles harbour the beta-galactoside-binding lectin galectin-3, which interacts directly with apical cargo in a glycan-dependent manner. These glycoproteins are mistargeted to the basolateral membrane in galectin-3-depleted cells, dedicating a central role to this lectin in raft-independent sorting as apical receptor. Here, we demonstrate that high-molecular-weight clusters are exclusively formed in the presence of galectin-3. Their stability is sensitive to increased carbohydrate concentrations, and cluster formation as well as apical sorting are perturbed in glycosylation-deficient Madin-Darby canine kidney (MDCK) II cells. Together, our data suggest that glycoprotein cross-linking by galectin-3 is required for apical sorting of non-raft-associated cargo.

• Author: Delphine Delacour; Christoph Greb; Annett Koch; Emma Salomonsson; Hakon Leffler; Andre Le Bivic; Ralf Jacob
• Department/s: Division of Microbiology, Immunology and Glycobiology - MIG
• Publishing year: 2007
• Language: English
• Pages: 379-388
• Publication/Series: Traffic: the International Journal of Intracellular Transport
• Volume: 8
• Issue: 4
• Links: http://dx.doi.org/10.1111/j.1600-0854.2007.00539.x
• Document type: Journal article
• Publisher: Wiley-Blackwell
• Topic: Microbiology in the medical area; Immunology in the medical area
• Keywords: polarized cells; glycoprotein sorting; apical transport; galectin
• Status: Published
• ISBN/ISSN/Other: ISSN: 1398-9219