|
|
 Previous Article | Table of Contents | Next Article 
Binding and internalization of recombinant human erythropoietin in murine
erythroid precursor cells
RA Mufson and TG Gesner
Erythropoietin (EPO) biosynthetically labelled with [35S]cysteine was
produced from Chinese hamster ovary (CHO) cells containing amplified copies
of human EPO cDNA. The glycosylated recombinant [35S]EPO, purified to
virtual radiochemical homogeneity, was biologically active. We studied the
interaction of this labeled recombinant EPO with erythroid precursor cells
from mice made anemic with phenylhydrazine. The [35S]-labeled molecule
bound to erythroid precursors in a time- and temperature-dependent manner.
The binding was specific for EPO, and neither insulin, transferrin,
epidermal growth factor, nor multiplication stimulating activity could
compete for EPO binding sites. In the presence of 0.2% sodium azide, which
blocks 80% to 90% of internalization, the recombinant molecule bound with
an apparent Kd of 750 pmol/L and 100 to 200 binding sites per cell at 37
degrees C. Asialo-EPO was a more effective competitor than sialated EPO for
the available binding sites. Thus, the enhanced biological specific
activity of asialo-EPO could result from its enhanced binding affinity. We
also studied recombinant human EPO labeled with 125I and found that it also
bound to the erythroid cells in a saturable and specific manner. After 90
minutes of incubation at 37 degrees C, most of the bound [35S]EPO was
internalized, whereas most of the [125I]EPO remained on the cell surface.
The reduced internalization of the iodinated molecule could account for the
previously reported functional deficit associated with iodination.
Volume 69,
Issue 5,
pp. 1485-1490,
05/01/1987
Copyright © 1987 by The American Society of Hematology
 CiteULike  Connotea  Del.icio.us  Digg  Reddit  Technorati What's this?
This article has been cited by other articles:
|
|
|
|
 
S. E. Juul, R. J. McPherson, L. A. Bauer, K. J. Ledbetter, C. A. Gleason, and D. E. Mayock
A Phase I/II Trial of High-Dose Erythropoietin in Extremely Low Birth Weight Infants: Pharmacokinetics and Safety
Pediatrics,
August 1, 2008;
122(2):
383 - 391.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
S. Chapel, P. Veng-Pedersen, R. J. Hohl, R. L. Schmidt, E. M. McGuire, and J. A. Widness
Changes in Erythropoietin Pharmacokinetics following Busulfan-Induced Bone Marrow Ablation in Sheep: Evidence for Bone Marrow as a Major Erythropoietin Elimination Pathway
J. Pharmacol. Exp. Ther.,
August 1, 2001;
298(2):
820 - 824.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
D. Savarese, H. Waitkus, F. M. Stewart, and M. Callery
Bloodless Medicine and Surgery
J Intensive Care Med,
January 1, 1999;
14(1):
20 - 33.
[PDF]
|
|
|
|
|
|
|
F. Verdier, P. Walrafen, N. Hubert, S. Chretien, S. Gisselbrecht, C. Lacombe, and P. Mayeux
Proteasomes Regulate the Duration of Erythropoietin Receptor Activation by Controlling Down-regulation of Cell Surface Receptors
J. Biol. Chem.,
June 9, 2000;
275(24):
18375 - 18381.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
