The transcytosis of divalent metal transporter 1 and apo-transferrin during iron uptake in intestinal epithelium.
Am J Physiol Gastrointest Liver Physiol
; 283(4): G965-74, 2002 Oct.
Article
em En
| MEDLINE
| ID: mdl-12223357
ABSTRACT
Caco-2 cells grown in bicameral chambers are a model system to study intestinal iron absorption. Caco-2 cells exhibit constitutive transport of iron from the apical (luminal) chamber to the basal (serosal) chamber that is enhanced by apo-transferrin in the basal chamber, with the apo-transferrin undergoing endocytosis to the apical portion of the cell. With the addition of iron to the apical surface, divalent metal transporter 1 (DMT1) on the brush-border membrane (BBM) undergoes endocytosis. These findings suggest that in Caco-2 cells DMT1 and apo-transferrin may cooperate in iron transport through transcytosis. To prove this hypothesis, we determined by confocal microscopy that, after addition of iron to the apical chamber, DMT1 from the BBM and Texas red apo-transferrin from the basal chamber colocalized in a perinuclear compartment. Colocalization was also observed by isolating endosomes from Caco-2 cells after ingestion of ultra-small paramagnetic particles from either the basal or apical chamber. The isolated endosomes contained both transferrin and DMT1 independent of the chamber from which the paramagnetic particles were endocytosed. These findings suggest that iron transport across intestinal epithelia may be mediated by transcytosis.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Apoproteínas
/
Transferrina
/
Proteínas de Transporte
/
Proteínas de Transporte de Cátions
/
Proteínas de Ligação ao Ferro
/
Mucosa Intestinal
/
Ferro
Tipo de estudo:
Prognostic_studies
Limite:
Humans
Idioma:
En
Ano de publicação:
2002
Tipo de documento:
Article