Transport of iron and other transition metals into cells as revealed by a fluorescent probe

W. Breuer*, S. Epsztejn, P. Millgram, I. Z. Cabantchik

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

176 Scopus citations

Abstract

Transport of nontransferrin-bound iron into cells is thought to be mediated by a facilitated mechanism involving either the trivalent form Fe(III) or the divalent form Fe(II) following reduction of Fe(III) at the cell surface. We have made use of the probe calcein, whose fluorescence is rapidly and stoichiometrically quenched by divalent metals such as Fe(II), Cu(II), Co(II), and Ni(II) and is minimally affected by variations in ionic strength, Ca(II) and Mg(II). Addition of Fe(II) salts to calcein-loaded human erythroleukemia K-562 cells elicited a slow quenching response that was markedly accelerated by the ionophore A-23187 and was reversed by membrane- permeant but not by impermeant chelators. These observations were confirmed by fluorescence imaging of cells. Other divalent metals such as Co(II), Ni(II), and Mn(II) permeated into cells at roughly similar rates, and their uptake, like that of Fe(II), was blocked by trifluoperazine, bepridil, and impermeant sulfhydryl-reactive organomercurials, indicating the operation of a common transport mechanism. This method could provide a versatile tool for studying the transport of iron and other transition metals into cells.

Original languageEnglish
Pages (from-to)C1354-C1361
JournalAmerican Journal of Physiology - Cell Physiology
Volume268
Issue number6 37-6
DOIs
StatePublished - 1995

Keywords

  • calcein
  • cobalt
  • fluorescence
  • imaging
  • manganese
  • nickel
  • transport

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