Roles of the N and C terminal domains of the interleukin-3 receptor alpha chain in receptor function.
Date
1997
Authors
Barry, S.
Korpelainen, E.
Sun, Q.
Stomski, F.
Moretti, P.
Wakao, H.
D'Andrea, R.
Vadas, M.
Lopez, A.
Goodall, G.
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Advisors
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Type:
Journal article
Citation
Blood, 1997; 89(3):842-852
Statement of Responsibility
S.C. Barry, E. Korpelainen, Q. Sun, F.C. Stomski, P.A.B. Moretti, H. Wakao, R.J. D’Andrea, M.A. Vadas, A.F. Lopez, and G.J. Goodall
Conference Name
Abstract
The interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor, and IL-5 receptor alpha chains are each composed of three extracellular domains, a transmembrane domain and a short intracellular region. Domains 2 and 3 constitute the cytokine receptor module (CRM), typical of the cytokine receptor superfamily; however, the function of the N-terminal domain is not known. We have investigated the functions of the N-terminal and C-terminal domains of the IL-3 receptor (IL-3R) alpha chain. We find that cells transfected with the receptor beta chain (h beta c) and a truncated IL-3R alpha that is devoid of the intracellular region fail to proliferate or to activate STAT5 in response to human IL-3, despite binding the IL-3 with affinity indistinguishable from that of full-length receptor. In addition, IL-3-induced phosphorylation of h beta c was not detected. Thus, the IL-3R alpha intracellular region does not contribute detectably to stabilization of the receptor/ligand complex, but is essential for signal propagation. In contrast, a truncated IL-3R alpha with the N-terminal domain deleted interacts functionally with the beta chain; mouse cells transfected with these receptor chains proliferate in response to human IL-3 and STAT5 transcription factor is activated. High- and low-affinity binding sites are retained, although the affinity for IL-3 is decreased 15-fold, indicating a significant role for the N-terminal domain in IL-3 binding.
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Copyright © 1997 by The American Society of Hematology