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Natural Resistance to Intracellular Infections: Natural Resistance–Associated Macrophage Protein 1 (Nramp1) Functions as a Ph-Dependent Manganese Transporter at the Phagosomal Membrane

Mutations at the natural resistance–associated macrophage protein 1 (Nramp1) locus cause susceptibility to infection with antigenically unrelated intracellular pathogens. Nramp1 codes for an integral membrane protein expressed in the lysosomal compartment of macrophages, and is recruited to the memb...

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Autores principales: Jabado, Nada, Jankowski, Andrzej, Dougaparsad, Samuel, Picard, Virginie, Grinstein, Sergio, Gros, Philippe
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 2000
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2193348/
https://www.ncbi.nlm.nih.gov/pubmed/11067873
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author Jabado, Nada
Jankowski, Andrzej
Dougaparsad, Samuel
Picard, Virginie
Grinstein, Sergio
Gros, Philippe
author_facet Jabado, Nada
Jankowski, Andrzej
Dougaparsad, Samuel
Picard, Virginie
Grinstein, Sergio
Gros, Philippe
author_sort Jabado, Nada
collection PubMed
description Mutations at the natural resistance–associated macrophage protein 1 (Nramp1) locus cause susceptibility to infection with antigenically unrelated intracellular pathogens. Nramp1 codes for an integral membrane protein expressed in the lysosomal compartment of macrophages, and is recruited to the membrane of phagosomes soon after the completion of phagocytosis. To define whether Nramp1 functions as a transporter at the phagosomal membrane, a divalent cation-sensitive fluorescent probe was designed and covalently attached to a porous particle. The resulting conjugate, zymosan–FF6, was ingested by macrophages and its fluorescence emission was recorded in situ after phagocytosis, using digital imaging. Quenching of the probe by Mn(2+) was used to monitor the flux of divalent cations across the phagosomal membrane in peritoneal macrophages obtained from Nramp1-expressing (+/+) and Nramp1-deficient (−/−) macrophages. Phagosomes from Nramp1(+/+) mice extrude Mn(2+) faster than their Nramp(−/−) counterparts. The difference in the rate of transport is eliminated when acidification of the phagosomal lumen is dissipated, suggesting that divalent metal transport through Nramp1 is H(+) dependent. These studies suggest that Nramp1 contributes to defense against infection by extrusion of divalent cations from the phagosomal space. Such cations are likely essential for microbial function and their removal from the phagosomal microenvironment impairs pathogenesis, resulting in enhanced bacteriostasis or bactericidal activity.
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spelling pubmed-21933482008-04-16 Natural Resistance to Intracellular Infections: Natural Resistance–Associated Macrophage Protein 1 (Nramp1) Functions as a Ph-Dependent Manganese Transporter at the Phagosomal Membrane Jabado, Nada Jankowski, Andrzej Dougaparsad, Samuel Picard, Virginie Grinstein, Sergio Gros, Philippe J Exp Med Original Article Mutations at the natural resistance–associated macrophage protein 1 (Nramp1) locus cause susceptibility to infection with antigenically unrelated intracellular pathogens. Nramp1 codes for an integral membrane protein expressed in the lysosomal compartment of macrophages, and is recruited to the membrane of phagosomes soon after the completion of phagocytosis. To define whether Nramp1 functions as a transporter at the phagosomal membrane, a divalent cation-sensitive fluorescent probe was designed and covalently attached to a porous particle. The resulting conjugate, zymosan–FF6, was ingested by macrophages and its fluorescence emission was recorded in situ after phagocytosis, using digital imaging. Quenching of the probe by Mn(2+) was used to monitor the flux of divalent cations across the phagosomal membrane in peritoneal macrophages obtained from Nramp1-expressing (+/+) and Nramp1-deficient (−/−) macrophages. Phagosomes from Nramp1(+/+) mice extrude Mn(2+) faster than their Nramp(−/−) counterparts. The difference in the rate of transport is eliminated when acidification of the phagosomal lumen is dissipated, suggesting that divalent metal transport through Nramp1 is H(+) dependent. These studies suggest that Nramp1 contributes to defense against infection by extrusion of divalent cations from the phagosomal space. Such cations are likely essential for microbial function and their removal from the phagosomal microenvironment impairs pathogenesis, resulting in enhanced bacteriostasis or bactericidal activity. The Rockefeller University Press 2000-11-06 /pmc/articles/PMC2193348/ /pubmed/11067873 Text en © 2000 The Rockefeller University Press This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Original Article
Jabado, Nada
Jankowski, Andrzej
Dougaparsad, Samuel
Picard, Virginie
Grinstein, Sergio
Gros, Philippe
Natural Resistance to Intracellular Infections: Natural Resistance–Associated Macrophage Protein 1 (Nramp1) Functions as a Ph-Dependent Manganese Transporter at the Phagosomal Membrane
title Natural Resistance to Intracellular Infections: Natural Resistance–Associated Macrophage Protein 1 (Nramp1) Functions as a Ph-Dependent Manganese Transporter at the Phagosomal Membrane
title_full Natural Resistance to Intracellular Infections: Natural Resistance–Associated Macrophage Protein 1 (Nramp1) Functions as a Ph-Dependent Manganese Transporter at the Phagosomal Membrane
title_fullStr Natural Resistance to Intracellular Infections: Natural Resistance–Associated Macrophage Protein 1 (Nramp1) Functions as a Ph-Dependent Manganese Transporter at the Phagosomal Membrane
title_full_unstemmed Natural Resistance to Intracellular Infections: Natural Resistance–Associated Macrophage Protein 1 (Nramp1) Functions as a Ph-Dependent Manganese Transporter at the Phagosomal Membrane
title_short Natural Resistance to Intracellular Infections: Natural Resistance–Associated Macrophage Protein 1 (Nramp1) Functions as a Ph-Dependent Manganese Transporter at the Phagosomal Membrane
title_sort natural resistance to intracellular infections: natural resistance–associated macrophage protein 1 (nramp1) functions as a ph-dependent manganese transporter at the phagosomal membrane
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2193348/
https://www.ncbi.nlm.nih.gov/pubmed/11067873
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