Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P17931 (galectin-3)
 2,860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The central aspect of epithelial cells is their polarized structure, characterized by two distinct domains of the plasma membrane, the apical and the basolateral membrane. Apical protein sorting requires various signals and different intracellular routes to the cell surface. The first apical targeting motif identified is the membrane anchoring of a polypeptide by glycosyl-phosphatidyl-inositol (GPI). A second group of apical signals involves N- and O-glycans, which are exposed to the luminal side of the sorting organelle. Sucrase-isomaltase (SI) and lactase-phlorizin hydrolase (LPH), which use separate transport platforms for trafficking, are two model proteins for the study of apical protein sorting. In contrast to LPH, SI associates with sphingolipid/cholesterol-enriched membrane microdomains or "lipid rafts". After exit form the trans-Golgi network (TGN), the two proteins travel in distinct vesicle populations, SAVs (SI-associated vesicles) and LAVs (LPH-associated vesicles) . Here, we report the identification of the lectin galectin-3 delivering non-raft-dependent glycoproteins in the lumen of LAVs in a carbohydrate-dependent manner. Depletion of galectin-3 from MDCK cells results in missorting of non-raft-dependent apical membrane proteins to the basolateral cell pole. This suggests a direct role of galectin-3 in apical sorting as a sorting receptor.
 ...
PMID:Requirement for galectin-3 in apical protein sorting. 1648 76

Epithelial cells are characterised by distinct apical and basolateral membrane domains that are separated by tight junctions. Establishment and maintenance of this polarity depend on specific gene expression and protein targeting to their correct location. Our former studies, performed with renal epithelial MDCK cells, revealed a new function for galectin-3, a member of a conserved family of lectins. There, galectin-3 is required for intracellular sorting and correct targeting of non-raft-associated glycoproteins to the apical plasma membrane. In the present study, we found transport defects of the intestinal brush border hydrolases lactase-phlorizin hydrolase (LPH) and dipeptidylpeptidase IV (DPPIV) in galectin-3-null mutant mice. We could show that, in enterocytes of wild-type mice, both glycoproteins directly interact with galectin-3 and transit through non-raft-dependent apical transport platforms. Therefore, this genetic analysis provides definitive evidence for the involvement of galectin-3 in protein intracellular trafficking in vivo. Further investigations revealed that gal3-null enterocytes also exhibit striking cytoarchitecture defects, with the presence of numerous and regular protrusions located along basolateral membranes. Moreover, beta-actin and villin, two characteristic markers of brush borders, become abnormally distributed along these atypical basolateral membranes in gal3(-/-) mice. Taken together, our results demonstrate that, in addition to a pivotal role in apical trafficking, galectin-3 also participates in epithelial morphogenesis in mouse enterocytes.
 ...
PMID:Loss of galectin-3 impairs membrane polarisation of mouse enterocytes in vivo. 1821 59