|
|
 Previous Article | Table of Contents | Next Article 
Role of pertussis toxin-sensitive guanosine triphosphate-binding proteins
in the response of erythroblasts to erythropoietin
BA Miller, K Foster, JD Robishaw, CF Whitfield, L Bell and JY Cheung
Department of Pediatrics, Milton S. Hershey Medical Center, Pennsylvania
State University, Hershey, PA 17033.
Human progenitor-derived erythroblasts have been recently shown to respond
to erythropoietin (Epo) with an increase in intracellular free calcium
concentration [Cac]. To explore the role of guanosine triphosphate
(GTP)-binding proteins in mediating the rise in [Cac], single day 10
erythroid burst forming unit (BFU-E)-derived erythroblasts loaded with
Fura-2 were pretreated with pertussis toxin (PT), stimulated with Epo, and
[Cac] measured over 18 minutes with fluorescence microscopy coupled to
digital video imaging. The [Cac] increase in day 10 erythroblasts
stimulated with Epo was blocked by pretreatment with PT in a dose-dependent
manner but not by heat- inactivated PT. These observations provided strong
evidence that a PT- sensitive GTP-binding protein is involved. To further
characterize the GTP-binding protein, day 10 erythroblast membrane
preparations were solubilized, electrophoresed, and immunoblotted with
antibodies specific for the known PT-sensitive G-protein subunits: the
three subtypes of Gia (1,2, and 3) and Goa, Gia1 or Gia3 and Gia2 were
identified but no Goa was found. To examine the influence of Epo on
adenylate cyclase activity, day 10 erythroblasts were initially treated
with Epo, isolated membrane preparations made, and cyclic adenosine
monophosphate (cAMP) production by adenylate cyclase in membrane
preparations in the presence of theophylline measured. Epo did not inhibit
but significantly stimulated adenylate cyclase activity. However, the
mechanism of increase of [Cac] appears to be independent of adenylate
cyclase stimulation because treatment of erythroblasts with the
cell-permeant dibutyryl cAMP failed to increase [Cac]. In summary,
pertussis toxin blocks the increase in [Cac] in erythroblasts after Epo
stimulation suggesting that this response is mediated through a pertussis
toxin-sensitive GTP-binding protein. Candidate PT-sensitive GTP-binding
proteins identified on day 10 erythroblasts were Gia 1, 2, or 3, but not
Goa.
Volume 77,
Issue 3,
pp. 486-492,
02/01/1991
Copyright © 1991 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:
|
|
|
|
 
C. Guillard, S. Chretien, A.-S. Pelus, F. Porteu, O. Muller, P. Mayeux, and V. Duprez
Activation of the Mitogen-activated Protein Kinases Erk1/2 by Erythropoietin Receptor via a Gi Protein beta gamma -Subunit-initiated Pathway
J. Biol. Chem.,
March 21, 2003;
278(13):
11050 - 11056.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. Ito, E. Kusano, Y. Furukawa, H. Yamamoto, S.-I. Takeda, T. Akimoto, O. Iimura, Y. Ando, and Y. Asano
Modulation of the erythropoietin-induced proliferative pathway by cAMP in vascular smooth muscle cells
Am J Physiol Cell Physiol,
December 1, 2002;
283(6):
C1715 - C1721.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
I. Karpati, I. Seres, J. Matyus, T. Ben, G. Paragh, Z. Varga, and G. K.
Which parameters affect cytosolic free calcium in polymorphonuclear leukocytes of haemodialysis patients?
Nephrol. Dial. Transplant.,
July 1, 2001;
16(7):
1409 - 1415.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
B. A. Miller, D. L. Barber, L. L. Bell, B. K. Beattie, M.-Y. Zhang, B. G. Neel, M. Yoakim, L. I. Rothblum, and J. Y. Cheung
Identification of the Erythropoietin Receptor Domain Required for Calcium Channel Activation
J. Biol. Chem.,
July 16, 1999;
274(29):
20465 - 20472.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
J. Y. Cheung, X.-Q. Zhang, K. Bokvist, D. L. Tillotson, and B. A. Miller
Modulation of Calcium Channels in Human Erythroblasts by Erythropoietin
Blood,
January 1, 1997;
89(1):
92 - 100.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
C. Guillard, S. Chretien, R. Jockers, S. Fichelson, P. Mayeux, and V. Duprez
Coupling of Heterotrimeric Gi Proteins to the Erythropoietin Receptor
J. Biol. Chem.,
January 12, 2001;
276(3):
2007 - 2014.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
