Open AccessFerroportin 1 is expressed basolaterally in rat kidney proximal tubule cells and iron excess increases its membrane trafficking
Author(s) -
Wolff Natascha A.,
Liu Wei,
Fenton Robert A.,
Lee WingKee,
Thévenod Frank,
Smith Craig P.
Publication year - 2011
Publication title -
journal of cellular and molecular medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.44
H-Index - 130
eISSN - 1582-4934
pISSN - 1582-1838
DOI - 10.1111/j.1582-4934.2009.00985.x
Subject(s) - dmt1 , endocytosis , microbiology and biotechnology , transferrin , transferrin receptor , apical membrane , brush border , endosome , cytosol , chemistry , epithelial polarity , kidney , reabsorption , ferroportin , biology , intracellular , biochemistry , transporter , membrane , receptor , endocrinology , vesicle , metabolism , gene , enzyme , iron homeostasis
Ferroportin 1 (FPN1) is an iron export protein expressed in liver and duodenum, as well as in reticuloendothelial macrophages. Previously, we have shown that divalent metal transporter 1 (DMT1) is expressed in late endosomes and lysosomes of the kidney proximal tubule (PT), the nephron segment responsible for the majority of solute reabsorption. We suggested that following receptor mediated endocytosis of transferrin filtered by the glomerulus, DMT1 exports iron liberated from transferrin into the cytosol. FPN1 is also expressed in the kidney yet its role remains obscure. As a first step towards determining the role of renal FPN1, we localized FPN1 in the PT. FPN1 was found to be located in association with the basolateral PT membrane and within the cytosolic compartment. FPN1 was not expressed on the apical brush‐border membrane of PT cells. These data support a role for FPN1 in vectorial export of iron out of PT cells. Furthermore, under conditions of iron loading of cultured PT cells, FPN1 was trafficked to the plasma membrane suggesting a coordinated cellular response to export excess iron and limit cellular iron concentrations.