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Blood, 15 November 2007, Vol. 110, No. 10, pp. 3582-3590.
Prepublished online as a Blood First Edition Paper on July 16, 2007; DOI 10.1182/blood-2007-01-070391.
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Submitted January 25, 2007
Accepted July 2, 2007
The Shc binding site of the c subunit of the GM-CSF/IL-3/IL-5 receptors is a negative regulator of hematopoiesis
Hayley S Ramshaw, Mark A Guthridge, Frank C Stomski, Emma F Barry, Lisa Ooms, Christina A Mitchell, C. Glenn Begley, and Angel F. Lopez*
Division of Human Immunology, The Cytokine Receptor Laboratory, Institute of Medical and Veterinary Science, Adelaide, SA, Australia
Department of Medicine, University of Adelaide, Adelaide, SA, Australia
Division of Human Immunology, Cell Growth and Differentiation Laboratory, Institute of Medical and Veterinary Science, Adelaide, SA, Australia
Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria, Australia
Hematology and Oncology Research, Amgen Inc., Thousand Oaks, CA, United States
* Corresponding author; email: angel.lopez{at}imvs.sa.gov.au.
Tyrosine and Serine phosphorylation of the common beta chain ( c) of the granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin (IL)-3 and IL-5 receptors is widely viewed as a general mechanism that provides positive inputs by coupling the receptor to signaling pathways that stimulate several cellular functions. We show here that despite the known action of Tyr577 in c to recruit Shc-PI3K pathway members, Tyr577 plays, surprisingly, a negative regulatory role in cell function and, that this is mediated, at least in part, through the uncoupling of SHIP from c. Fetal liver cells from c/ IL-3-/- mice expressing human GM-CSF receptor chain and c Tyr577Phe mutant showed enhanced colony formation and expansion of progenitor cells in response to GM-CSF. Dissection of these activities revealed that basal survival was increased, as well as cytokine-stimulated proliferation. As expected the recruitment and activation of Shc was abolished, but interestingly, Gab-2 and Akt phosphorylation increased. Significantly, the activation of PI3K was enhanced and prolonged, accompanied by loss of SHIP activity. These results reveal a previously unrecognised negative signalling role for Tyr577 in c and demonstrate that uncoupling Shc from cytokine receptors enhances PI3K signalling as well as survival and proliferation

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T. R. Hercus, D. Thomas, M. A. Guthridge, P. G. Ekert, J. King-Scott, M. W. Parker, and A. F. Lopez
The granulocyte-macrophage colony-stimulating factor receptor: linking its structure to cell signaling and its role in disease
Blood,
August 13, 2009;
114(7):
1289 - 1298.
[Abstract]
[Full Text]
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