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. 1983 Apr;80(8):2263–2266. doi: 10.1073/pnas.80.8.2263

Binding of apotransferrin to K562 cells: explanation of the transferrin cycle.

R D Klausner, G Ashwell, J van Renswoude, J B Harford, K R Bridges
PMCID: PMC393799  PMID: 6300904

Abstract

The binding of apotransferrin to the transferrin receptor on the surface of human leukemic K562 cells was found to be significantly less tight than that of the holoprotein, diferric transferrin. The finding that both ligands displayed linear Scatchard plots with similar receptor number (approximately equal to 150,000 per cell) and mutually inhibit each other's binding suggested that they bind to the same receptor. Both the dissociation and association rate of apotransferrin were markedly increased (28-fold and 15-fold, respectively) at pH 7.2 compared to pH 4.8. Using the values of these binding parameters, we propose a mechanism to account for the recycling of transferrin subsequent to internalization and residence within an acidic nonlysosomal organelle where iron is removed.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Aisen P., Listowsky I. Iron transport and storage proteins. Annu Rev Biochem. 1980;49:357–393. doi: 10.1146/annurev.bi.49.070180.002041. [DOI] [PubMed] [Google Scholar]
  2. Bridges K., Harford J., Ashwell G., Klausner R. D. Fate of receptor and ligand during endocytosis of asialoglycoproteins by isolated hepatocytes. Proc Natl Acad Sci U S A. 1982 Jan;79(2):350–354. doi: 10.1073/pnas.79.2.350. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Dautry-Varsat A., Ciechanover A., Lodish H. F. pH and the recycling of transferrin during receptor-mediated endocytosis. Proc Natl Acad Sci U S A. 1983 Apr;80(8):2258–2262. doi: 10.1073/pnas.80.8.2258. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Goldstein J. L., Anderson R. G., Brown M. S. Coated pits, coated vesicles, and receptor-mediated endocytosis. Nature. 1979 Jun 21;279(5715):679–685. doi: 10.1038/279679a0. [DOI] [PubMed] [Google Scholar]
  5. Harford J., Bridges K., Ashwell G., Klausner R. D. Intracellular dissociation of receptor-bound asialoglycoproteins in cultured hepatocytes. A pH-mediated nonlysosomal event. J Biol Chem. 1983 Mar 10;258(5):3191–3197. [PubMed] [Google Scholar]
  6. Karin M., Mintz B. Receptor-mediated endocytosis of transferrin in developmentally totipotent mouse teratocarcinoma stem cells. J Biol Chem. 1981 Apr 10;256(7):3245–3252. [PubMed] [Google Scholar]
  7. Lozzio C. B., Lozzio B. B. Human chronic myelogenous leukemia cell-line with positive Philadelphia chromosome. Blood. 1975 Mar;45(3):321–334. [PubMed] [Google Scholar]
  8. Marsh M., Wellsteed J., Kern H., Harms E., Helenius A. Monensin inhibits Semliki Forest virus penetration into culture cells. Proc Natl Acad Sci U S A. 1982 Sep;79(17):5297–5301. doi: 10.1073/pnas.79.17.5297. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Maxfield F. R. Weak bases and ionophores rapidly and reversibly raise the pH of endocytic vesicles in cultured mouse fibroblasts. J Cell Biol. 1982 Nov;95(2 Pt 1):676–681. doi: 10.1083/jcb.95.2.676. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Octave J. N., Schneider Y. J., Crichton R. R., Trouet A. Transferrin uptake by cultured rat embryo fibroblasts. The influence of temperature and incubation time, subcellular distribution and short-term kinetic studies. Eur J Biochem. 1981 Apr;115(3):611–618. [PubMed] [Google Scholar]
  11. Pastan I. H., Willingham M. C. Receptor-mediated endocytosis of hormones in cultured cells. Annu Rev Physiol. 1981;43:239–250. doi: 10.1146/annurev.ph.43.030181.001323. [DOI] [PubMed] [Google Scholar]
  12. Pearse B. M. Coated vesicles from human placenta carry ferritin, transferrin, and immunoglobulin G. Proc Natl Acad Sci U S A. 1982 Jan;79(2):451–455. doi: 10.1073/pnas.79.2.451. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Steer C. J., Ashwell G. Studies on a mammalian hepatic binding protein specific for asialoglycoproteins. Evidence for receptor recycling in isolated rat hepatocytes. J Biol Chem. 1980 Apr 10;255(7):3008–3013. [PubMed] [Google Scholar]
  14. Tolleshaug H. Binding and internalization of asialo-glycoproteins by isolated rat hepatocytes. Int J Biochem. 1981;13(1):45–51. doi: 10.1016/0020-711x(81)90135-x. [DOI] [PubMed] [Google Scholar]
  15. Tycko B., Maxfield F. R. Rapid acidification of endocytic vesicles containing alpha 2-macroglobulin. Cell. 1982 Mar;28(3):643–651. doi: 10.1016/0092-8674(82)90219-7. [DOI] [PubMed] [Google Scholar]
  16. van Renswoude J., Bridges K. R., Harford J. B., Klausner R. D. Receptor-mediated endocytosis of transferrin and the uptake of fe in K562 cells: identification of a nonlysosomal acidic compartment. Proc Natl Acad Sci U S A. 1982 Oct;79(20):6186–6190. doi: 10.1073/pnas.79.20.6186. [DOI] [PMC free article] [PubMed] [Google Scholar]

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