Iron Imports. V. Transport of iron through the intestinal epithelium.
Iron absorption across the brush-border membrane requires divalent metal transporter 1 (DMT1), whereas ferroportin (FPN) and hephaestin are required for exit across the basolateral membrane. However, how iron passes across the enterocyte is poorly understood. Both chaperones and transcytosis have been postulated to account for intracellular iron transport. With iron feeding, DMT1 undergoes endocytosis and FPN translocates from the apical cytosol to the basolateral membrane. The fluorescent metallosensor calcein offered to the basolateral surface of enterocytes is found in endosomes in the apical compartment, and its fluorescence is quenched when iron is offered to the apical surface. These experiments are consistent with vesicular iron transport as a possible pathway for intracellular iron transport.
Feist-Weiller Cancer Center and Department of Medicine, Louisiana State University Health Sciences Center, 1501 Kings Highway, Shreveport, LA 71130, USA.
Yuxiang
Y
Ma
Mary
M
Yeh
Kwo-Yih
KY
Yeh
Jonathan
J
Glass
D000818:Animals; D018938:Caco-2 Cells; D027682:Cation Transport Proteins / Q000502:physiology; D020895:Enterocytes / Q000502:physiology; D006801:Humans; D007408:Intestinal Absorption / Q000502:physiology*; D007413:Intestinal Mucosa / Q000378:metabolism*; D007501:Iron / Q000378:metabolism*; D033862:Iron-Binding Proteins / Q000502:physiology; D008565:Membrane Proteins / Q000502:physiology; D021381:Protein Transport / Q000502:physiology; D051381:Rats; D000098742:Ferroportin; D000099236:Solute Carrier Family 11, Member 2
D027682:Cation Transport Proteins; D007501:Iron; D033862:Iron-Binding Proteins; D008565:Membrane Proteins; D000098742:Ferroportin; D000099236:Solute Carrier Family 11, Member 2; C492163:Heph, protein, rat