Dictyostelium Nramp1, which is structurally and functionally similar tomammalian DMT1 transporter, mediates phagosomal iron efflux

Simona Buracco, Barbara Peracino, Raffaella Cinquetti, Elena Signoretto, Alessandra Vollero, Francesca Imperiali, Michela Castagna, Elena Bossi, Salvatore Bozzaro

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

The Nramp (Slc11) protein family is widespread in bacteria and eukaryotes, and mediates transport of divalent metals across cellular membranes. The social amoeba Dictyostelium discoideum has two Nramp proteins. Nramp1, like its mammalian ortholog (SLC11A1), is recruited to phagosomal and macropinosomal membranes, and confers resistance to pathogenic bacteria. Nramp2 is located exclusively in the contractile vacuole membrane and controls, synergistically with Nramp1, iron homeostasis. It has long been debated whether mammalian Nramp1 mediates iron import or export from phagosomes. By selectively loading the iron-chelating fluorochrome calcein inmacropinosomes, we show that Dictyostelium Nramp1 mediates iron efflux from macropinosomes in vivo. To gain insight in ion selectivity and the transport mechanism, the proteins were expressed in Xenopus oocytes. Using a novel assay with calcein, and electrophysiological and radiochemical assays, we show that Nramp1, similar to rat DMT1 (also known as SLC11A2), transports Fe2+ and manganese, not Fe3+ or copper. Metal ion transport is electrogenic and proton dependent. By contrast, Nramp2 transports only Fe2+ in a non-electrogenic and proton-independent way. These differences reflect evolutionary divergence of the prototypical Nramp2 protein sequence compared to the archetypical Nramp1 and DMT1 proteins.

Original languageEnglish
Pages (from-to)3304-3316
Number of pages13
JournalJournal of Cell Science
Volume128
Issue number17
DOIs
Publication statusPublished - 2015

Fingerprint

Dictyostelium
Iron
Ion Transport
Membranes
Protons
Metals
Bacteria
Phagosomes
Amoeba
Manganese
Xenopus
Vacuoles
Eukaryota
Fluorescent Dyes
Oocytes
Copper
Carrier Proteins
Homeostasis
natural resistance-associated macrophage protein 1
Proteins

Keywords

  • Bacterial infection
  • DMT1
  • Iron homeostasis
  • Macropinocytosis
  • Nramp1
  • Nramp2

ASJC Scopus subject areas

  • Cell Biology

Cite this

Buracco, S., Peracino, B., Cinquetti, R., Signoretto, E., Vollero, A., Imperiali, F., ... Bozzaro, S. (2015). Dictyostelium Nramp1, which is structurally and functionally similar tomammalian DMT1 transporter, mediates phagosomal iron efflux. Journal of Cell Science, 128(17), 3304-3316. https://doi.org/10.1242/jcs.173153

Dictyostelium Nramp1, which is structurally and functionally similar tomammalian DMT1 transporter, mediates phagosomal iron efflux. / Buracco, Simona; Peracino, Barbara; Cinquetti, Raffaella; Signoretto, Elena; Vollero, Alessandra; Imperiali, Francesca; Castagna, Michela; Bossi, Elena; Bozzaro, Salvatore.

In: Journal of Cell Science, Vol. 128, No. 17, 2015, p. 3304-3316.

Research output: Contribution to journalArticle

Buracco, S, Peracino, B, Cinquetti, R, Signoretto, E, Vollero, A, Imperiali, F, Castagna, M, Bossi, E & Bozzaro, S 2015, 'Dictyostelium Nramp1, which is structurally and functionally similar tomammalian DMT1 transporter, mediates phagosomal iron efflux', Journal of Cell Science, vol. 128, no. 17, pp. 3304-3316. https://doi.org/10.1242/jcs.173153
Buracco, Simona ; Peracino, Barbara ; Cinquetti, Raffaella ; Signoretto, Elena ; Vollero, Alessandra ; Imperiali, Francesca ; Castagna, Michela ; Bossi, Elena ; Bozzaro, Salvatore. / Dictyostelium Nramp1, which is structurally and functionally similar tomammalian DMT1 transporter, mediates phagosomal iron efflux. In: Journal of Cell Science. 2015 ; Vol. 128, No. 17. pp. 3304-3316.
@article{01de2ae8c2274cdfb71c699963ec5abf,
title = "Dictyostelium Nramp1, which is structurally and functionally similar tomammalian DMT1 transporter, mediates phagosomal iron efflux",
abstract = "The Nramp (Slc11) protein family is widespread in bacteria and eukaryotes, and mediates transport of divalent metals across cellular membranes. The social amoeba Dictyostelium discoideum has two Nramp proteins. Nramp1, like its mammalian ortholog (SLC11A1), is recruited to phagosomal and macropinosomal membranes, and confers resistance to pathogenic bacteria. Nramp2 is located exclusively in the contractile vacuole membrane and controls, synergistically with Nramp1, iron homeostasis. It has long been debated whether mammalian Nramp1 mediates iron import or export from phagosomes. By selectively loading the iron-chelating fluorochrome calcein inmacropinosomes, we show that Dictyostelium Nramp1 mediates iron efflux from macropinosomes in vivo. To gain insight in ion selectivity and the transport mechanism, the proteins were expressed in Xenopus oocytes. Using a novel assay with calcein, and electrophysiological and radiochemical assays, we show that Nramp1, similar to rat DMT1 (also known as SLC11A2), transports Fe2+ and manganese, not Fe3+ or copper. Metal ion transport is electrogenic and proton dependent. By contrast, Nramp2 transports only Fe2+ in a non-electrogenic and proton-independent way. These differences reflect evolutionary divergence of the prototypical Nramp2 protein sequence compared to the archetypical Nramp1 and DMT1 proteins.",
keywords = "Bacterial infection, DMT1, Iron homeostasis, Macropinocytosis, Nramp1, Nramp2",
author = "Simona Buracco and Barbara Peracino and Raffaella Cinquetti and Elena Signoretto and Alessandra Vollero and Francesca Imperiali and Michela Castagna and Elena Bossi and Salvatore Bozzaro",
year = "2015",
doi = "10.1242/jcs.173153",
language = "English",
volume = "128",
pages = "3304--3316",
journal = "Journal of Cell Science",
issn = "0021-9533",
publisher = "Company of Biologists Ltd",
number = "17",

}

TY - JOUR

T1 - Dictyostelium Nramp1, which is structurally and functionally similar tomammalian DMT1 transporter, mediates phagosomal iron efflux

AU - Buracco, Simona

AU - Peracino, Barbara

AU - Cinquetti, Raffaella

AU - Signoretto, Elena

AU - Vollero, Alessandra

AU - Imperiali, Francesca

AU - Castagna, Michela

AU - Bossi, Elena

AU - Bozzaro, Salvatore

PY - 2015

Y1 - 2015

N2 - The Nramp (Slc11) protein family is widespread in bacteria and eukaryotes, and mediates transport of divalent metals across cellular membranes. The social amoeba Dictyostelium discoideum has two Nramp proteins. Nramp1, like its mammalian ortholog (SLC11A1), is recruited to phagosomal and macropinosomal membranes, and confers resistance to pathogenic bacteria. Nramp2 is located exclusively in the contractile vacuole membrane and controls, synergistically with Nramp1, iron homeostasis. It has long been debated whether mammalian Nramp1 mediates iron import or export from phagosomes. By selectively loading the iron-chelating fluorochrome calcein inmacropinosomes, we show that Dictyostelium Nramp1 mediates iron efflux from macropinosomes in vivo. To gain insight in ion selectivity and the transport mechanism, the proteins were expressed in Xenopus oocytes. Using a novel assay with calcein, and electrophysiological and radiochemical assays, we show that Nramp1, similar to rat DMT1 (also known as SLC11A2), transports Fe2+ and manganese, not Fe3+ or copper. Metal ion transport is electrogenic and proton dependent. By contrast, Nramp2 transports only Fe2+ in a non-electrogenic and proton-independent way. These differences reflect evolutionary divergence of the prototypical Nramp2 protein sequence compared to the archetypical Nramp1 and DMT1 proteins.

AB - The Nramp (Slc11) protein family is widespread in bacteria and eukaryotes, and mediates transport of divalent metals across cellular membranes. The social amoeba Dictyostelium discoideum has two Nramp proteins. Nramp1, like its mammalian ortholog (SLC11A1), is recruited to phagosomal and macropinosomal membranes, and confers resistance to pathogenic bacteria. Nramp2 is located exclusively in the contractile vacuole membrane and controls, synergistically with Nramp1, iron homeostasis. It has long been debated whether mammalian Nramp1 mediates iron import or export from phagosomes. By selectively loading the iron-chelating fluorochrome calcein inmacropinosomes, we show that Dictyostelium Nramp1 mediates iron efflux from macropinosomes in vivo. To gain insight in ion selectivity and the transport mechanism, the proteins were expressed in Xenopus oocytes. Using a novel assay with calcein, and electrophysiological and radiochemical assays, we show that Nramp1, similar to rat DMT1 (also known as SLC11A2), transports Fe2+ and manganese, not Fe3+ or copper. Metal ion transport is electrogenic and proton dependent. By contrast, Nramp2 transports only Fe2+ in a non-electrogenic and proton-independent way. These differences reflect evolutionary divergence of the prototypical Nramp2 protein sequence compared to the archetypical Nramp1 and DMT1 proteins.

KW - Bacterial infection

KW - DMT1

KW - Iron homeostasis

KW - Macropinocytosis

KW - Nramp1

KW - Nramp2

UR - http://www.scopus.com/inward/record.url?scp=84946073573&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84946073573&partnerID=8YFLogxK

U2 - 10.1242/jcs.173153

DO - 10.1242/jcs.173153

M3 - Article

VL - 128

SP - 3304

EP - 3316

JO - Journal of Cell Science

JF - Journal of Cell Science

SN - 0021-9533

IS - 17

ER -