title: Cellular location of proteins related to iron absorption and transport.
abstract: K562 erythroleukemia cells and IEC6 rat cells were examined using confocal microscopy and antibodies raised against DMT-1 (Nramp-2, DCT-1), transferrin receptor (CD71), beta(3) integrin (CD61), mobilferrin (calreticulin), and Hephaestin. The cellular location of each of these proteins was identified by immunofluorescence in both saponin-permeabilized and non-permeabilized cells. Fluorescent reactivity was observed on or near the cell surface of each of these proteins, suggesting that they might participate in surface membrane transport of iron. Fluorescence was observed in the region of the cytoplasm with each antibody to include beta(3) integrin and transferrin receptor. It was pronounced in cells incubated with mobilferrin, Hephaestin, and DMT-1 antibodies. Speckled nuclear fluorescence was observed in cells incubated with anti-DMT-1. While these observations are descriptive, they demonstrate that there are significant concentrations of DMT-1, mobilferrin, and Hephaestin in the cytoplasmic region of cells. This suggests that there may be intracellular roles for these proteins in addition to their serving to transit iron across the cell surface membrane.
authors.affiliation: University of South Alabama, Mobile, Alabama, USA.
authors.forename: Marcia J
authors.initials: MJ
authors.lastname: Simovich
authors.forename: Marcel E
authors.initials: ME
authors.lastname: Conrad
authors.forename: Jay N
authors.initials: JN
authors.lastname: Umbreit
authors.forename: Elizabeth G
authors.initials: EG
authors.lastname: Moore
authors.forename: Lucille N
authors.initials: LN
authors.lastname: Hainsworth
authors.forename: Hilary K
authors.initials: HK
authors.lastname: Smith
mesh_terms: D000042:Absorption; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D027682:Cation Transport Proteins; D002451:Cell Compartmentation; D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D039661:Integrin beta3; D017136:Ion Transport; D007501:Iron / Q000493:pharmacokinetics*; D033862:Iron-Binding Proteins; D008565:Membrane Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism; D021381:Protein Transport; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D011990:Receptors, Transferrin / Q000378:metabolism; D014407:Tumor Cells, Cultured; D000099236:Solute Carrier Family 11, Member 2
chemical_list: D015703:Antigens, CD; D002352:Carrier Proteins; D027682:Cation Transport Proteins; D039661:Integrin beta3; D007501:Iron; D033862:Iron-Binding Proteins; D008565:Membrane Proteins; D010980:Platelet Membrane Glycoproteins; D011506:Proteins; D011990:Receptors, Transferrin; D000099236:Solute Carrier Family 11, Member 2; C492164:HEPH protein, human; C492163:Heph, protein, rat; C085511:mobilferrin