Leishmania chagasi: Uptake of iron bound to lactoferrin or transferrin requires an iron reductase

Mary E. Wilson, Troy S. Lewis, Melissa A. Miller, Michael L. McCormick, Bradley E. Britigan

Research output: Contribution to journalArticle

44 Scopus citations

Abstract

Leishmania chagasi can utilize iron bound to transferrin, lactoferrin, or other chelates. We investigated the mechanism of iron uptake. Promastigotes preferentially took up iron in a reduced rather than an oxidized form, suggesting that extracellular iron must be reduced prior to internalization. Similar to literature reports, a 70-kDa protein in promastigote membrane-containing microsomes bound to [125I]-labeled transferrin. However, [125I]lactoferrin and [125I]albumin also bound a similar 70-kDa protein, suggesting that binding might not be specific. Both total and fractionated promastigotes exhibited an NADPH-dependent iron reductase activity. In contrast to trypanosomes, which take up transferrin through a specific receptor, these data support a model in which a parasite-associated or secreted reductase reduces ferric to ferrous iron, decreasing its affinity for the extracellular chelate and allowing it to be readily internalized by the parasite. This could account for the ability of the parasite to utilize iron from multiple sources in diverse host environments.

Original languageEnglish (US)
Pages (from-to)196-207
Number of pages12
JournalExperimental Parasitology
Volume100
Issue number3
DOIs
StatePublished - Mar 1 2002

ASJC Scopus subject areas

  • Parasitology
  • Immunology
  • Infectious Diseases

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