Brefeldin A enhances receptor-mediated transcytosis of transferrin in filter-grown Madin-Darby canine kidney cells
The effects of brefeldin A (BFA) on transferrin (Tf) transcellular transport, Tf receptor (TfR) distribution, and TfR-mediated endocytosis in filter-grown Madin-Darby canine kidney (MDCK) cells were studied. BFA (1.6 micrograms/ml) markedly enhanced the transcytosis of 125I-labeled Tf (125I-Tf) in b...
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Veröffentlicht in: | The Journal of biological chemistry 1992-07, Vol.267 (19), p.13446-13450 |
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Zusammenfassung: | The effects of brefeldin A (BFA) on transferrin (Tf) transcellular transport, Tf receptor (TfR) distribution, and TfR-mediated
endocytosis in filter-grown Madin-Darby canine kidney (MDCK) cells were studied. BFA (1.6 micrograms/ml) markedly enhanced
the transcytosis of 125I-labeled Tf (125I-Tf) in both apical-to-basal and basal-to-apical directions; yet, BFA did not enhance
the transcytosis of either native horseradish peroxidase (HRP) or membrane-bound HRP-poly(L-lysine) conjugates. Furthermore,
this enhanced transcytosis of 125I-Tf was abolished either by competition with excess unlabeled Tf or by incubation at temperatures
less than or equal to 25 degrees C. In addition, BFA treatment to MDCK cells: (a) increased 125I-Tf specific binding to the
apical membrane and decreased 125I-Tf specific binding to the basal membrane; (b) decreased TfR recycling at the basolateral
membrane; (c) altered the apical/basolateral distribution of TfRs in favor of the apical side; and (d) markedly increased
59Fe extraction, but not transcytosis, from apically endocytosed 59Fe-loaded Tf. These effects are consistent with a model
in which BFA alters the traffic pattern of internalized Tf by decreasing basolateral TfR recycling, while diverting the nonrecycled
fraction to the apical side of the cell. Our results indicate that, unlike the reported inhibition of polymeric IgA transcytosis
(Hunziker, W., Whitney, J. A., and Mellman, I. (1991) Cell 67, 617-627), BFA can enhance the transcytosis of Tf in MDCK cells.
Thus, by altering the intracellular traffic of ligand-receptor complexes, BFA can elicit either a decrease or an increase
in transcytosis depending on the nature of the intracellular receptor processing. |
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ISSN: | 0021-9258 1083-351X |
DOI: | 10.1016/S0021-9258(18)42231-4 |