HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 293/4/C1383    most recent 00054.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by Shvartsman, M. Articles by Cabantchik, Z. I. Search for Related Content PubMed PubMed Citation Articles by Shvartsman, M. Articles by Cabantchik, Z. I.

CELLULAR METABOLISM

Non-transferrin-bound iron reaches mitochondria by a chelator-inaccessible mechanism: biological and clinical implications

¹Department of Biological Chemistry, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem; and ²Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel

Submitted 7 February 2007 ; accepted in final form 26 July 2007

Non-transferrin-bound iron, commonly found in the plasma of iron-overloaded individuals, permeates into cells via pathways independent of the transferrin receptor. This may lead to excessive cellular accumulation of labile iron followed by oxidative damage and eventually organ failure. Mitochondria are the principal destination of iron in cells and a primary site of prooxidant generation, yet their mode of acquisition of iron is poorly understood. Using fluorescent probes sensitive to iron or to reactive oxygen species, targeted to cytosol and/or to mitochondria, we traced the ingress of labile iron into these compartments by fluorescence microscopy and quantitative fluorimetry. We observed that 1) penetration of non-transferrin-bound iron into the cytosol and subsequently into mitochondria occurs with barely detectable delay and 2) loading of the cytosol with high-affinity iron-binding chelators does not abrogate iron uptake into mitochondria. Therefore, a fraction of non-transferrin-bound iron acquired by cells reaches the mitochondria in a nonlabile form. The physiological role of occluded iron transfer might be to confer cells with a "safe and efficient cytosolic iron corridor" to mitochondria. However, such a mechanism might be deleterious in iron-overload conditions, because it could lead to surplus accumulation of iron in these critical organelles.

transport; fluorescence; oxidative stress

This article has been cited by other articles:

				Y.-S. Sohn, W. Breuer, A. Munnich, and Z. I. Cabantchik Redistribution of accumulated cell iron: a modality of chelation with therapeutic implications Blood, February 1, 2008; 111(3): 1690 - 1699. [Abstract] [Full Text] [PDF]