Galectin-4-regulated delivery of glycoproteins to the brush border membrane of enterocyte-like cells.
Traffic
; 10(4): 438-50, 2009 Apr.
Article
en En
| MEDLINE
| ID: mdl-19192249
ABSTRACT
We have previously reported that silencing of galectin-4 expression in polarized HT-29 cells perturbed apical biosynthetic trafficking and resulted in a phenotype similar to the inhibitor of glycosylation, 1-benzyl-2-acetamido-2-deoxy-beta-d-galactopyranoside (GalNAcalpha-O-bn). We now present evidence of a lipid raft-based galectin-4-dependent mechanism of apical delivery of glycoproteins in these cells. First, galectin-4 recruits the apical glycoproteins in detergent-resistant membranes (DRMs) because these glycoproteins were depleted in DRMs isolated from galectin-4-knockdown (KD) HT-29 5M12 cells. DRM-associated glycoproteins were identified as ligands for galectin-4. Structural analysis showed that DRMs were markedly enriched in a series of complex N-glycans in comparison to detergent-soluble membranes. Second, in galectin-4-KD cells, the apical glycoproteins still exit the Golgi but accumulated inside the cells, showing that their recruitment within lipid rafts and their apical trafficking required the delivery of galectin-4 at a post-Golgi level. This lectin that is synthesized on free cytoplasmic ribosomes is externalized from HT-29 cells mostly in the apical medium and follows an apical endocytic-recycling pathway that is required for the apical biosynthetic pathway. Together, our data show that the pattern of N-glycosylation of glycoproteins serves as a recognition signal for endocytosed galectin-4, which drives the raft-dependent apical pathway of glycoproteins in enterocyte-like HT-29 cells.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Glicoproteínas
/
Membrana Celular
/
Enterocitos
/
Galectina 4
Límite:
Humans
Idioma:
En
Revista:
Traffic
Asunto de la revista:
FISIOLOGIA
Año:
2009
Tipo del documento:
Article
País de afiliación:
Francia