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Analysis of the steady state binding, internalization, and degradation of human interferon-alpha2.
- Source :
- Journal of Biological Chemistry; April 1986, Vol. 261 Issue: 11 p4993-4996, 4p
- Publication Year :
- 1986
-
Abstract
- Scatchard analyses of the equilibrium binding of radiolabeled human interferon-alpha2 (huIFN-alpha2) to Madin-Darby bovine kidney cells previously exposed to subsaturating concentrations of IFN-alpha showed approximately a 50% decrease in the number of cell surface receptors and no change in the apparent dissociation constant, Kd, compared with cells not exposed to interferon. The steady state equations describing the interaction of polypeptide ligands with cell surface receptors under physiological conditions (Wiley, H.S., and Cunningham, D.D. (1981) Cell 25, 433-440) have allowed us to determine, under steady state conditions, the rate of insertion of receptors into the cell membrane, the endocytic rate constant of occupied receptors, the rate constant of turnover of unoccupied receptors, and the rate of hydrolysis of internalized ligand. Our results indicate that occupied and unoccupied interferon receptors are cleared from the cell surface at approximately the same rate. This suggests that the down-regulation of the huIFN-alpha2 receptor on Madin-Darby bovine kidney cells by huIFN-alpha2 differs from that of several other surface receptors for polypeptide hormones and growth factors analyzed on cultured cells in that the binding of huIFN-alpha2 to its receptor does not increase the rate of receptor endocytosis.
Details
- Language :
- English
- ISSN :
- 00219258 and 1083351X
- Volume :
- 261
- Issue :
- 11
- Database :
- Supplemental Index
- Journal :
- Journal of Biological Chemistry
- Publication Type :
- Periodical
- Accession number :
- ejs55798067
- Full Text :
- https://doi.org/10.1016/S0021-9258(19)89204-9