Subcellular localization of iron regulatory proteins to Golgi and ER membranes

Stephanie M. Patton, Domingo J. Piñero, Nodar Surguladze, John Beard, James R. Connor

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Interaction between iron regulatory proteins and iron responsive elements on certain mRNAs is at the core of regulation of intracellular iron homeostasis. Previous results suggested that in cultured cells iron regulatory proteins (IRPs) exist in cytosolic and microsomal subcellular locations and that this distribution is affected by cellular iron status. In this study, we tested the hypothesis that the membrane-associated fractions of iron regulatory proteins are specifically in the endoplasmic reticulum and Golgi membranes. Confocal microscopy revealed that IRP1 could be co-localized to the endoplasmic reticulum and the Golgi apparatus. To examine the intracellular distribution of IRPs biochemically, we used rats fed normal or iron-deficient diets. As expected, the IRPs were found predominantly in the cytosolic fraction. However, subfractionation of crude microsomal preparations revealed IRP1 in the Golgi apparatus. In animals fed an iron-deficient diet, IRP1 was found in the Golgi apparatus and the endoplasmic reticulum. To identify the mechanisms and factors involved in the localization of iron regulatory proteins in the cytosol and membrane fractions, cells were treated with a phorbol ester, a protein kinase C inhibitor (chelerythrine), hydrogen peroxide, interleukin-1β, and 1,2-bis-(o-aminophenoxy)-ethane-N,N,-N′N′-tetraacetic acid tetraacetoxy-methyl ester. The results indicate that iron-regulatory-protein-binding activity in the membrane fraction can be altered by cell stress or iron status and that phosphorylation plays a role in the translocation. As a result of this study we propose a novel model for intracellular distribution of IRPs and identify differences between the two iron regulatory proteins.

Original languageEnglish (US)
Pages (from-to)4365-4373
Number of pages9
JournalJournal of Cell Science
Volume118
Issue number19
DOIs
StatePublished - Oct 1 2005

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Iron-Regulatory Proteins
Membranes
Iron
Golgi Apparatus
Endoplasmic Reticulum
Diet
Ethane
Protein C Inhibitor
Phorbol Esters
Protein Kinase Inhibitors
Interleukin-1
Protein Binding
Confocal Microscopy
Cytosol
Protein Kinase C
Hydrogen Peroxide
Cultured Cells
Esters
Homeostasis
Phosphorylation

All Science Journal Classification (ASJC) codes

  • Cell Biology

Cite this

Patton, Stephanie M. ; Piñero, Domingo J. ; Surguladze, Nodar ; Beard, John ; Connor, James R. / Subcellular localization of iron regulatory proteins to Golgi and ER membranes. In: Journal of Cell Science. 2005 ; Vol. 118, No. 19. pp. 4365-4373.
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Subcellular localization of iron regulatory proteins to Golgi and ER membranes. / Patton, Stephanie M.; Piñero, Domingo J.; Surguladze, Nodar; Beard, John; Connor, James R.

In: Journal of Cell Science, Vol. 118, No. 19, 01.10.2005, p. 4365-4373.

Research output: Contribution to journalArticle

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