Publication

Iron regulatory factor expressed from recombinant baculovirus: conversion between the RNA-binding apoprotein and Fe-S cluster containing aconitase

Lukas Kühn
1993
Article
Résumé

Iron regulatory factor (IRF) is a cytoplasmic mRNA-binding protein that coordinates post-transcriptionally the expression of several important proteins in iron metabolism. Binding of IRF to iron-responsive elements (IRE) in the 5' untranslated region (UTR) of ferritin and erythroid 5-aminolevulinic acid-synthase mRNAs inhibits their translation, whereas binding to IREs in the 3' UTR of transferrin receptor (TfR) mRNA prevents the degradation of this mRNA. IRF binds RNA strongly after iron deprivation, but is inactive, yet present, under conditions of high cellular iron supply. Recently, IRF was also shown to have aconitase activity indicating the existence of an Fe-S cluster in the protein. In the current study we expressed human IRF in insect cells from recombinant baculovirus and analysed IRE-binding and aconitase activities under various culture conditions. Newly made apoprotein, synthesized in the absence of iron, was fully active in IRE-binding, but showed no aconitase activity. In contrast, IRF made by cells grown in high iron medium bound RNA poorly, but exhibited high aconitase activity with a Km of 9.2 microM for cis-aconitate. Apo-IRF was converted in vitro to active aconitase by Fe-S cluster-generating conditions, and under the same conditions lost its RNA-binding capacity. These results indicate that the two activities are mutually exclusive and controlled through formation of the Fe-S cluster.

À propos de ce résultat
Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Graph Chatbot

Chattez avec Graph Search

Posez n’importe quelle question sur les cours, conférences, exercices, recherches, actualités, etc. de l’EPFL ou essayez les exemples de questions ci-dessous.

AVERTISSEMENT : Le chatbot Graph n'est pas programmé pour fournir des réponses explicites ou catégoriques à vos questions. Il transforme plutôt vos questions en demandes API qui sont distribuées aux différents services informatiques officiellement administrés par l'EPFL. Son but est uniquement de collecter et de recommander des références pertinentes à des contenus que vous pouvez explorer pour vous aider à répondre à vos questions.