title: Iron regulatory proteins control a mucosal block to intestinal iron absorption.
abstract: Mammalian iron metabolism is regulated systemically by the hormone hepcidin and cellularly by iron regulatory proteins (IRPs) that orchestrate a posttranscriptional regulatory network. Through ligand-inducible genetic ablation of both IRPs in the gut epithelium of adult mice, we demonstrate that IRP deficiency impairs iron absorption and promotes mucosal iron retention via a ferritin-mediated "mucosal block." We show that IRP deficiency does not interfere with intestinal sensing of body iron loading and erythropoietic iron need, but rather alters the basal expression of the iron-absorption machinery. IRPs thus secure sufficient iron transport across absorptive enterocytes by restricting the ferritin "mucosal block" and define a basal set point for iron absorption upon which IRP-independent systemic regulatory inputs are overlaid.
authors.affiliation: European Molecular Biology Laboratory, Meyerhofstrasse 1, Heidelberg 69117, Germany. galy@embl.de
authors.forename: Bruno
authors.initials: B
authors.lastname: Galy
authors.forename: Dunja
authors.initials: D
authors.lastname: Ferring-Appel
authors.forename: Christiane
authors.initials: C
authors.lastname: Becker
authors.forename: Norbert
authors.initials: N
authors.lastname: Gretz
authors.forename: Hermann-Josef
authors.initials: HJ
authors.lastname: Gröne
authors.forename: Klaus
authors.initials: K
authors.lastname: Schümann
authors.forename: Matthias W
authors.initials: MW
authors.lastname: Hentze
mesh_terms: D000818:Animals; D027682:Cation Transport Proteins / Q000378:metabolism; D020895:Enterocytes / Q000378:metabolism*; D005293:Ferritins / Q000235:genetics / Q000378:metabolism; D007408:Intestinal Absorption; D017136:Ion Transport; D007501:Iron / Q000378:metabolism*; D035925:Iron-Regulatory Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009154:Mutation; D014158:Transcription, Genetic; D000098742:Ferroportin
chemical_list: D027682:Cation Transport Proteins; D035925:Iron-Regulatory Proteins; D000098742:Ferroportin; D005293:Ferritins; D007501:Iron