Study of the Transferrin Receptor Using a Cytotoxic Human Transferrin-Ricin a Chain Conjugate
The A chain of ricin which catalytically inactivates eukaryotic ribosomes inhibits cellular protein synthesis only after entering the cell. Although attachment of pure A chain to cell membranes has not been demonstrated (Raso, 1981), it is toxic at high concentrations indicating that cells can inefficiently internalize this 30,000 MW protein. Cytotoxicity is enhanced 103–105-fold however by recombining A chain either with its natural B chain subunit or with alternative carriers which deliver it to the cell surface and facilitate access to ribosomes within the cytoplasm. Thus, cyto-toxins possessing different cell receptor selectivities can be designed by coupling A chain to antibody or ligand carriers with appropriately chosen specificity characteristics. This controlled cytotoxic action has stimulated interest from the standpoint of eliminating undesirable cells for therapeutic reasons but is equally important for cell biology studies.
KeywordsTransferrin Receptor Ferric Ammonium Citrate Human Transferrin Chain Conjugate Cellular Protein Synthesis
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- Fairbanks, V.F. and Beutler, E., 1977, Iron metabolism. in: Hematology, W.J. Williams, ed., McGraw-Hill, New York.Google Scholar