Colocalization of ferroportin-1 with hephaestin on the basolateral membrane of human intestinal absorptive cells

J Cell Biochem. 2007 Jul 1;101(4):1000-10. doi: 10.1002/jcb.21392.

Abstract

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Blotting, Western
  • Caco-2 Cells
  • Cation Transport Proteins / genetics
  • Cation Transport Proteins / metabolism*
  • Cell Membrane / metabolism*
  • Electrophoresis, Polyacrylamide Gel
  • Fluorescent Antibody Technique
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Humans
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Microscopy, Confocal
  • Receptors, Transferrin / metabolism
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Transfection

Substances

  • Cation Transport Proteins
  • HEPH protein, human
  • Membrane Proteins
  • Receptors, Transferrin
  • Recombinant Fusion Proteins
  • metal transporting protein 1
  • Green Fluorescent Proteins