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Iron targeting to mitochondria in erythroid cells
P Ponka1, A D Sheftel, A-S Zhang
1Lady Davis Institute, Jewish General Hospital and Department of Physiology, McGill University, 3755 Cote Ste-Catherine Road, Montreal, QC, Canada H3T 1E2. prem.ponka@mcgill.edu
Biochemical Society Transactions
|August 28, 2002
Summary
Erythroid cells efficiently synthesize haem by uniquely controlling iron. Inhibiting endosome mobility in these cells significantly reduced iron incorporation into haem, suggesting a role for endosome-mitochondria interaction in this process.
Area of Science:
- Cell Biology
- Biochemistry
- Hematology
Background:
- Immature erythroid cells exhibit a high capacity for haem synthesis.
- Iron metabolism in erythroid cells is uniquely controlled to support high haem production.
- Iron must traverse endosomes and mitochondria to reach ferrochelatase for haem synthesis.
Purpose of the Study:
- To investigate the role of endosome mobility in iron transfer for haem synthesis.
- To determine if inhibiting endosome movement affects iron incorporation into haem.
Main Methods:
- Utilized reticulocytes (immature red blood cells).
- Applied wortmannin (myosin light-chain kinase inhibitor) and W-7 (calmodulin antagonist) to inhibit endosome mobility.
- Tracked iron-59 ((59)Fe) incorporation into haem from labelled endosomes.
- Employed confocal microscopy with fluorescently labelled transferrin and mitochondria.
Main Results:
- Inhibition of endosome mobility significantly decreased (59)Fe incorporation into haem.
- Wortmannin and W-7 treatments reduced the rate of iron transfer to haem.
- Confocal microscopy supported the interaction between endosomes and mitochondria.
Conclusions:
- Endosome mobility and potential contact with mitochondria are crucial for efficient iron utilization in erythroid cells.
- This interaction facilitates the targeted delivery of iron for haem synthesis.
- The findings support a model of transient mitochondria-endosome interaction for iron transfer.