Interaction of acidic isoferritins with human promyelocytic HL60 cells

Abstract

We have used undifferentiated human promyelocytic HL60 cells to study the binding of radioiodinated human ferritin in vitro. Specific binding of human heart ferritin could be demonstrated at 37 degrees C, whereas no binding of liver ferritin could be found. The uptake of labelled heart ferritin was abolished by incubation at 4 degrees C, by prior treatment of the HL60 cells with pronase and by the addition of human plasma to the medium. On the other hand, the addition of excess unlabelled human liver or rat liver ferritin had no effect on the uptake of labelled human heart ferritin. Dissociation studies showed that about 55% of the bound heart ferritin radioactivity could be released by incubation with medium alone and at least 90% with excess unlabelled heart ferritin. Over 70% of the dissociated ferritin could be precipitated with polyclonal anti-ferritin serum or trichloroacetic acid. More than two-thirds of the radioactivity which could not be released after washing in medium alone was recovered in the soluble intracellular fraction following cell lysis. Almost all of the soluble radioactivity could be precipitated with the polyclonal antiserum, indicating that very little lysosomal degradation of internalized heart ferritin had occurred. The present studies demonstrate a protein-mediated binding mechanism for acidic isoferritins on HL60 cells. These observations agree with published evidence that ferritin is often associated with cell membranes and are consistent with a possible role for the protein in the regulation of haematopoiesis or in iron transfer.

Binding and uptake of exogenous isoferritins by cultured human erythroid precursor cells

“…Ferritin--especially acidic, H-subunit rich isoferri tin-has been reported to bind to membranes of human cell lines, including T-cell lines (Anderson et al, 1989;Konijn et al 1 990), HeLa cells (Bretscher & Thomson, 1983). the promyelocytic cell line HL60 (Covell & Cook, 1988). the erythroleukaemia cell line K562 (Fargion et al 1988;Covell et a], 1987) and recently also to normal human erythroid cells (Konijn et a/, 199 1;Fargion et al, 1992).…”

Oligodendrocytes and myelination: The role of iron

“…Since then, ferritin receptors have been reported in binding studies in variety of cell types including rat (Mack et al, 1985), pig and human hepatocytes , guinea pig reticulocytes (Blight and Morgan, 1987), Molt4 T lymphoid cells (Moss et al, 1992), K562 erythroleukemia cell line (Fargion et al, 1988), HL-60 promyelocytic cell line (Covell and Cook, 1988), T lymphocytes (Fargion et al, 1991) and erythroid precursors (Gelvan et al, 1996). In a series of binding experiments, Hulet et al showed that saturable and specific H-ferritin receptor(s) existed in white matter tracts of the rodent and human brain and demonstrated in cell culture studies that ferritin receptors were unique to oligodendrocytes (Hulet et al , 2000(Hulet et al , 2002.…”

Mutated recombinant human heavy-chain ferritins and myelosuppression in vitro and in vivo: a link between ferritin ferroxidase activity and biological function.

“…The rhu H-ferritin muteins with alterations to different extents on the outer surface of the molecule (115, Ml, 9cd), in the hydrophobic channel (91, R2), in the hydrophilic channel (174), or in the inner surface (A2, A3, A4) manifested suppressive activity, suggesting that myeloid activity is not located at these sites. It is reasonable, however, to assume that the initiation of inhibitory activity is exerted at least in part through specific interaction of H-ferritin with a membrane binding site, such as that noted on human myeloid leukemia cell lines established to grow in culture (36)(37)(38). However, the simple interaction of H-ferritin with its binding site on the cell is probably not alone sufficient for inhibitory activity.…”