Transferrin receptor regulation is coupled to intracellular ferritin in proliferating and differentiating HL60 leukemia cells

Rhyner, K; Taetle, Raymond; Bering, Harriet; To, Dong

doi:10.1002/jcp.1041250333

Cited by 18 publications

(5 citation statements)

References 23 publications

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“…This estimation is similar to previously reported subunit molecular weights of transferrin receptors isolated from other cell types (Hamilton et al 1979, Seligman et al 1979, Omary et al 1980, Enns & Sussman 1981, Haynes et al 1981, Sutherland et al 1981, Bleil & Bretscher 1982, Schneider et al 1982, Fuller & Simons 1986. The affinity of receptors present on intact cells and in detergent-solubilized U937 cell extracts was in the nM range, also consistent with previously reported results (Hamilton et al 1979, May et al 1984, Musgrove et al 1984, Taetle et al 1985, Fuller & Simons 1986, Nishimura et al 1986). In addition, we demonstrated a large pool of intracellular transferrin U937 transferrin binding sites.…”

Section: Discussionsupporting

confidence: 90%

Plasma membrane and intracellular pools of transferrin receptors decline during in vitro cultivation of U937 cells

Salcedo¹,

Fleit²

1991

Cell Proliferation

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Transferrin receptor expression in the monocyte-like cell line U937 was investigated during in vitro cultivation. U937 cells expressed a single class of high affinity surface transferrin receptors (KD approximately 4 nM), with apparent subunit Mr of 90-95,000 Da as determined by SDS-reducing PAGE. [125I]-transferrin binding studies on detergent-solubilized cells revealed that half to two-thirds of the total functional binding sites were located intracellularly. Radioligand binding, immunofluorescence and flow cytometry studies were performed on intact, detergent-solubilized, or saponin-permeabilized cells, using either transferrin or the anti-transferrin receptor monoclonal antibody OKT9 IgG. These studies demonstrated that functional and antigenic transferrin receptor levels were maximal on cells 24 h after subculture at low density and declined during the culture period. Scatchard analysis of radioligand binding data suggested that the decline in functional transferrin binding sites resulted from a decline in the number of available receptors. These results demonstrate that in U937 cells there is a density-dependent regulation of transferrin receptor expression, resulting in a loss of functional and antigenic receptors from both plasma membrane and intracellular locations.

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Section: Discussionsupporting

confidence: 90%

Plasma membrane and intracellular pools of transferrin receptors decline during in vitro cultivation of U937 cells

Salcedo¹,

Fleit²

1991

Cell Proliferation

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“…This is in agreement with immunohistochemical data on testicular Tf binding sites (Brown, 1985). However, the cellular uptake of Tf-bound iron by different cell types can be influenced in a complex manner by marked effects of Tf and iron on the number of Tf receptors and the ferritin content (Rhyner et al, 1985;Rao et al, 1986). Such effects may result in altered kinetics of iron uptake by isolated and cultured cells.…”

Section: Discussionsupporting

confidence: 89%

“…Tf receptors are mainly present on immature, undifferentiated cells and the number of receptors decline when cells differentiate (Rhyner et al, 1985;Petraki et al, 1986). In this context, spermatogenic cells may be considered as immature cells.…”

Section: Discussionmentioning

confidence: 99%

Transport of transferrin‐bound iron into rat Sertoli cells and spermatids

Toebosch¹,

Kroos

Grootegoed³

1987

Int J of Andrology

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Transferrin (Tf), a major secretory protein of Sertoli cells, may transport iron to spermatogenic cells. This was assessed by measuring the uptake of Fe from 59Fe-125I-labelled rat Tf by Sertoli cells and round spermatids in vitro. Uptake of Fe from labelled Tf by Sertoli cells after a 72-h pre-incubation period was linear for 20 h (approximately 18 pmol/10(6) cells/20 h), whereas the uptake of Fe from labelled Tf by round spermatids after a 16-h pre-incubation period reached a plateau by 2 h (approximately 5 pmol/10(6) cells/2 h). The corresponding net uptake of Tf by both cell types was less than 0.1 pmol. High speed supernatants prepared from Sertoli cells and spermatids labelled with 59Fe-125I-Tf were fractionated by gel permeation chromatography. Separate peaks of protein-bound 59Fe and 125I-Tf were observed. Protein bound 59Fe could be precipitated with an antiserum to rat ferritin. It is concluded that iron from exogenous Tf is transported into Sertoli cells and round spermatids in vitro, and is complexed to intracellular ferritin. However, the present results do not exclude the possibility that Sertoli cell Tf may serve purposes other than iron transport.

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“…The factor regulating the number of transferrin receptors must be determined. Cellular ferritin seems to be an important regulator of myeloid differentiation [19] [20] in HL60 cells, a promyelocytic leukemia cell line. Ward et al [21] showed that intracellular heme, rather than ferritin, modulates the number of transferrin receptors on Hela cells.…”

Section: Discussionmentioning

confidence: 99%

Erythroblast transferrin receptors and transferrin kinetics in iron deficiency and various anemias

et al. 1987

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To clarify the role of transferrin receptors in cases of altered iron metabolism in clinical pathological conditions, we studied: number of binding sites; affinity; and recycling kinetics of transferrin receptors on human erythroblasts. Since transferrin receptors are mainly present on erythroblasts, the number of surface transferrin receptors was determined by assay of binding of 125I-transferrin and the percentage of erythroblasts in bone marrow mononuclear cells. The number of binding sites on erythroblasts from patients with an iron deficiency anemia was significantly greater than in normal subjects (p less than 0.01). Among those with an aplastic anemia, hemolytic anemia, myelodysplastic syndrome, and polycythemia vera compared to normal subjects, there were no considerable differences in the numbers of binding sites. The dissociation constants (Kd) were measured using Scatchard analysis. The apparent Kd was unchanged (about 10 nmol/L) in patients and normal subjects. The kinetics of endocytosis and exocytosis of 125I-transferrin, examined by acid treatment, revealed no variations in recycling kinetics among the patients and normal subjects. These data suggest that iron uptake is regulated by modulation of the number of surface transferrin receptors, thereby reflecting the iron demand of the erythroblast.

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Transferrin receptor regulation is coupled to intracellular ferritin in proliferating and differentiating HL60 leukemia cells

Cited by 18 publications

References 23 publications

Plasma membrane and intracellular pools of transferrin receptors decline during in vitro cultivation of U937 cells

Plasma membrane and intracellular pools of transferrin receptors decline during in vitro cultivation of U937 cells

Transport of transferrin‐bound iron into rat Sertoli cells and spermatids

Erythroblast transferrin receptors and transferrin kinetics in iron deficiency and various anemias

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