Regulation of divalent metal transporter expression in human intestinal epithelial cells following exposure to non-haem iron

A number of regulatory factors including dietary iron levels can dramatically alter the expression of the intestinal iron transporter DMT1. Here we show that Caco-2 cells exposed to iron for 4 h exhibited a significant decrease in plasma membrane DMTI protein, though total cellular DMTI levels were unaltered. Following biotinylation of cell surface proteins, there was a significant increase in intracellular biotin-labelled DMTI in iron-exposed cells. Furthermore, iron-treatment increased levels of DMT1 co-localised with LAMP1, suggesting that the initial response of intestinal epithelial cells to iron involves internalisation and targeting of DMTI transporter protein towards a late endosomal/lysosomal compartment. (c) 2005 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.