Low molecular weight iron in guinea pig reticulocytes

Pollack, Simeon; Campana, Theresa; Weaver, Janet

doi:10.1002/ajh.2830190110

Cited by 25 publications

(6 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…haemochromatosis: Jacobs, 1977;Grohlich et al, 1979;Crichton, 1979;Morgan, 1977;Fontecave and Pierre, 1991;Britton et al, 1990;Nielson et al, 1993). The nature of the low-molecular-mass iron pool is presently unclear, but it has in the past been postulated to represent iron chelated with citrate (Morley and Bezhorovainy, 1983), phosphate (Pollack et al, 1985), amino acids (Bakkeren et al, 1985;Deighton and Hider, 1989) and ATP (Weaver and Pollack, 1989). However, given the apparently high affinity and kinetic lability of iron-InsP.…”

Section: ;mentioning

confidence: 99%

Inhibition of iron-catalysed hydroxyl radical formation by inositol polyphosphates: a possible physiological function for myo-inositol hexakisphosphate

Hawkins¹,

Poyner²,

Jackson³

et al. 1993

Biochemical Journal

129

View full text Add to dashboard Cite

1. The ability of myo-inositol polyphosphates to inhibit iron-catalysed hydroxyl radical formation was studied in a hypoxanthine/xanthine oxidase system [Graf, Empson and Eaton (1987) J. Biol. Chem. 262, 11647-11650]. Fe3+ present in the assay reagents supported some radical formation, and a standard assay, with 5 microM Fe3+ added, was used to investigate the specificity of compounds which could inhibit radical generation. 2. InsP6 (phytic acid) was able to inhibit radical formation in this assay completely. In this respect it was similar to the effects of the high affinity Fe3+ chelator Desferral, and dissimilar to the effects of EDTA which, even at high concentrations, still allowed detectable radical formation to take place. 3. The six isomers of InsP5 were purified from an alkaline hydrolysate of InsP6 (four of them as two enantiomeric mixtures), and they were compared with InsP6 in this assay. Ins(1,2,3,4,6)P5 and D/L-Ins(1,2,3,4,5)P5 were similar to InsP6 in that they caused a complete inhibition of iron-catalysed radical formation at > 30 microM. Ins(1,3,4,5,6)P5 and D/L-Ins(1,2,4,5,6)P5, however, were markedly less potent than InsP6, and did not inhibit radical formation completely; even when Ins(1,3,4,5,6)P5 was added up to 600 microM, significant radical formation was still detected. Thus InsP5s lacking 2 or 1/3 phosphates are in this respect qualitatively different from InsP6 and the other InsP5s. 4. scyllo-Inositol hexakisphosphate was also tested, and although it caused a greater inhibition than Ins(1,3,4,5,6)P5, it too still allowed detectable free radical formation even at 600 microM. 5. We conclude that the 1,2,3 (equatorial-axial-equatorial) phosphate grouping in InsP6 has a conformation that uniquely provides a specific interaction with iron to inhibit totally its ability to catalyse hydroxyl radical formation; we suggest that a physiological function of InsP6 might be to act as a 'safe' binding site for iron during its transport through the cytosol or cellular organelles.

show abstract

Section: ;mentioning

confidence: 99%

Inhibition of iron-catalysed hydroxyl radical formation by inositol polyphosphates: a possible physiological function for myo-inositol hexakisphosphate

Hawkins¹,

Poyner²,

Jackson³

et al. 1993

Biochemical Journal

129

View full text Add to dashboard Cite

show abstract

“…Fe, on first entering the cell, mixes transiently in a chelatable pool in which it is bound to low-Mr ligands (Pippard et al, 1982;Mulligan et al, 1986). This appears to be the case in reticulocytes, lymphocytes and Chang cells and also in cells derived from bone marrow, liver, kidney, brain and muscle (Primosigh & Thomas, 1968;Mansour et al, 1972;Borova et al, 1973;White et al, 1976;Nunez et al, 1978;Milsom & Batey, 1979;LaCross & Linder, 1980;Pollack et al, 1985;Mulligan et al, 1986;Bomford et al, 1986). The low-Mr Fe pool in lymphocytes has been quantified by Bomford et al (1986), who found the total Fe in the cytosol to be 15 greater than that in the combined high-Mr Fe-containing pools of that cell.…”

Section: Discussionmentioning

confidence: 89%

Mitochondria have Fe(III) receptors

Weaver

Zhan

Pollack

1990

Biochemical Journal

View full text Add to dashboard Cite

Recent work has provided new evidence that ATP is the major constituent of the low-Mr iron pool in the reticulocyte. The interaction of the iron complex of ATP with mitochondria was investigated in the present experiments. When ATP-Fe3+ was incubated with mitochondria, Fe3+, free of ATP, bound with high affinity to Fe3+ receptors on the mitochondria. The binding was saturable and reversible. Iron which was complexed to PPi, nitrilotriacetate, citrate, ADP and GTP also showed saturable binding to mitochondria; Fe3+ complexed to AMP bound non-specifically, as did Fe2+/ascorbate complexed to AMP bound non-specifically, as did Fe2+/ascorbate and Fe2+/dithionite.

show abstract

“…Cellular chelatable iron pool was postulated on the basis of kinetic considerations (Jacobs, 1977). Its chemical nature remains largely unknown (Romslo, 1980;Pollack et al, 1985;Bomford et al, 1986), since it is difficult to judge the physiological significance of various iron compounds isolated after cell disruption. Recent findings of Fuchs et al (1990) that iron withdrawal suppresses and iron supplementation induces glutathione peroxidase (GSHPx) mRNA levels suggests that GSHPx mRNA levels can be used as a more sensitive, though indirect indicator of cellular chelatable iron levels.…”

Section: Discussionmentioning

confidence: 99%

Inhibition of heme synthesis decreases transferrin receptor expression in mouse erythroleukemia cells

Hradilek

Fuchs

Neuwirt

1992

Journal Cellular Physiology

View full text Add to dashboard Cite

The coordination of transferrin receptor (TfR) expression and heme synthesis was investigated in mouse erythroleukemia (MEL) cells of line 707 treated with heme synthesis inhibitors or in a variant line Fw genetically deficient in heme synthesis. Cells of line 707 were induced for differentiation by 5 mM hexamethylene bisacetamide (HMBA). TfR expression increased in the course of induction, as judged by increased TfR mRNA synthesis, increased cytoplasmic TfR mRNA level, and by the increased number of cellular 125I-Tf binding sites. Addition of 0.1 mM succinylacetone (SA) decreased cellular TfR to the level comparable with the uninduced cells. The decrease was reverted by the iron chelator desferrioxamine (DFO) but not by exogenous hemin. In short-term (1-2 hours) incubation, SA inhibited 59Fe incorporation from transferrin into heme, whereas total cellular 59Fe uptake was increased. A decrease in TfR mRNA synthesis was apparent after 2 hours of SA treatment. Conversely, glutathione peroxidase mRNA synthesis, previously shown to be inducible by iron, was increased by SA treatment. Cells of heme deficient line Fw did not increase the number of Tf binding sites after the induction of differentiation by 5 mM sodium butyrate. SA had no effect on TfR expression in Fw cells. The results suggest that the depletion of cellular non-heme iron due to the increase in heme synthesis maintains a high level of transferrin receptor expression in differentiating erythroid cells even after the cessation of cell division.

show abstract

Low molecular weight iron in guinea pig reticulocytes

Cited by 25 publications

References 18 publications

Inhibition of iron-catalysed hydroxyl radical formation by inositol polyphosphates: a possible physiological function for myo-inositol hexakisphosphate

Inhibition of iron-catalysed hydroxyl radical formation by inositol polyphosphates: a possible physiological function for myo-inositol hexakisphosphate

Mitochondria have Fe(III) receptors

Inhibition of heme synthesis decreases transferrin receptor expression in mouse erythroleukemia cells

Contact Info

Product

Resources

About