Colocalization of ferroportin-1 with hephaestin on the basolateral membrane of human intestinal absorptive cells.
An iron exporter ferroportin-1 (FPN-1) and a multi-copper oxidase hephaestin (Heph) are predicted to be expressed on the basolateral membrane of the enterocyte and involved in the processes of iron export across the basolateral membrane of the enterocyte. However, it is not clear where these proteins are exactly located in the intestinal absorptive cell. We examined cellular localization of FPN-1 and Heph in the intestinal absorptive cells using the fully differentiated Caco-2 cells. Confocal microscope study showed that FPN-1 and Heph are located on the basolateral membrane and they are associated with the transferrin receptor (TfR) in fully differentiated Caco-2 cells grown on microporous membrane inserts. However, Heph protein was not detected in the crypt cell-like proliferating Caco-2 cell. In stably transfected human intestinal absorptive cells expressing human FPN-1 modified by the addition of GFP at the C-terminus, we show that FPN-1-GFP is located on the basolateral membrane and it is associated with Heph suggesting the possibility that FPN-1 might associate and interact with Heph in the process of iron exit across the basolateral membrane of intestinal absorptive cell.
Han
Okhee
O
Department of Nutritional Sciences, Pennsylvania State University, University Park, PA 16802, USA. ouh1@psu.edu
Kim
Eun-Young
EY
D015153:Blotting, Western; D018938:Caco-2 Cells; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005455:Fluorescent Antibody Technique; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D018613:Microscopy, Confocal; D011990:Receptors, Transferrin / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D000098742:Ferroportin
D027682:Cation Transport Proteins; C492164:HEPH protein, human; D008565:Membrane Proteins; D011990:Receptors, Transferrin; D011993:Recombinant Fusion Proteins; D000098742:Ferroportin; D049452:Green Fluorescent Proteins