The University of Southampton
University of Southampton Institutional Repository

A Study of Nramp1 function and targeting

A Study of Nramp1 function and targeting
A Study of Nramp1 function and targeting

Nramp1 is a member of a family of divalent cation transporters found in a variety of species. Mammalian Nramp1 is found exclusively in cells of haematopoietic lineage, namely monocytes/macrophages and polymorphonuclear leukocytes. Studies in mice have shown Nramp1 to confer resistance to a number of taxonomically and antigenically distinct organisms including Leishmania, Salmonella and Mycobacteria. It is recruited to phagolysosomes upon ingestion of bacteria where it is believed to affect the microenvironment within the phagolysosome. Two hypotheses have been formulated: one in which Nramp1 depletes the microenvironment of iron, starving the bacteria; and the other in which Nramp1 supplies iron for radical production and active attack of the bacteria.

Through the use of in vitro expression systems, induction studies in murine macrophages and sequence analysis, the following has been achieved. Nramp1 is regulated by its own substrate; iron, but also by oxygen derived radicals. In addition putative sites for this type of regulation have been identified in the promoter sequence.

Stable transfectant cell lines containing constitutively expressed Nramp1 grow at a slower rate compared to controls, as measured by cell staining and [3H]-thymidine uptake. These cell lines also show greater resistance to superoxide-induced stress, and attenuation of PKCbI protein levels, transcription of which is sensitive to labile iron pool concentrations. Together the results imply that Nramp1 may act to sequester iron in an intracellular vesicular system.

Lastly analysis of EGFP wildtype and mutant Nramp1 tagged proteins indicates that N-terminal phosphorylation of Nramp1 is not important in its targeting, as has been suggested. It is also shown that under an appropriate stimulus Nramp1 can translocate to the plasma membrane; the functional significance of this is discussed.

University of Southampton
Baker, Stephen Timothy
Baker, Stephen Timothy

Baker, Stephen Timothy (2002) A Study of Nramp1 function and targeting. University of Southampton, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

Nramp1 is a member of a family of divalent cation transporters found in a variety of species. Mammalian Nramp1 is found exclusively in cells of haematopoietic lineage, namely monocytes/macrophages and polymorphonuclear leukocytes. Studies in mice have shown Nramp1 to confer resistance to a number of taxonomically and antigenically distinct organisms including Leishmania, Salmonella and Mycobacteria. It is recruited to phagolysosomes upon ingestion of bacteria where it is believed to affect the microenvironment within the phagolysosome. Two hypotheses have been formulated: one in which Nramp1 depletes the microenvironment of iron, starving the bacteria; and the other in which Nramp1 supplies iron for radical production and active attack of the bacteria.

Through the use of in vitro expression systems, induction studies in murine macrophages and sequence analysis, the following has been achieved. Nramp1 is regulated by its own substrate; iron, but also by oxygen derived radicals. In addition putative sites for this type of regulation have been identified in the promoter sequence.

Stable transfectant cell lines containing constitutively expressed Nramp1 grow at a slower rate compared to controls, as measured by cell staining and [3H]-thymidine uptake. These cell lines also show greater resistance to superoxide-induced stress, and attenuation of PKCbI protein levels, transcription of which is sensitive to labile iron pool concentrations. Together the results imply that Nramp1 may act to sequester iron in an intracellular vesicular system.

Lastly analysis of EGFP wildtype and mutant Nramp1 tagged proteins indicates that N-terminal phosphorylation of Nramp1 is not important in its targeting, as has been suggested. It is also shown that under an appropriate stimulus Nramp1 can translocate to the plasma membrane; the functional significance of this is discussed.

Text
884979.pdf - Version of Record
Available under License University of Southampton Thesis Licence.
Download (38MB)

More information

Published date: 2002

Identifiers

Local EPrints ID: 464846
URI: http://eprints.soton.ac.uk/id/eprint/464846
PURE UUID: 0e777ae4-0944-46ab-9b40-40a6f6dc681c

Catalogue record

Date deposited: 05 Jul 2022 00:04
Last modified: 05 Jul 2022 03:19

Export record

Contributors

Author: Stephen Timothy Baker

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×