The primary binding subunit of the human interleukin-4 receptor is also a component of the interleukin-13 receptor.
Interleukin (IL)-13 elicits a subset of the biological activities of the related IL-4. The basis of this functional similarity is that their specific cell-surface receptors (called IL-13R and IL-4R) are distinct, yet are complex and share a common subunit(s). The IL-4R primary binding subunit (called IL-4R alpha) does not by itself bind IL-13. We show that the ability of IL-13 to partially compete for IL-4 binding to some human cell types depended on co-expression of IL-4R and IL-13R. However, IL-13 binding was always associated with IL-4 binding. Hyper-expression of IL-4R alpha on cells expressing both IL-4R and IL-13R decreased their binding affinity for IL-4, abrogated the ability of IL-13 to compete for IL-4 binding, and yet had no effect on IL-13R properties. Anti-human IL-4R alpha monoclonal antibodies which blocked the biological function and binding of IL-4 also blocked the function and binding of IL-13. These data show that IL-4R alpha is a secondary component of IL-13R.
Zurawski
S M
SM
Department of Molecular Biology, DNAX Research Institute of Cellular and Molecular Biology, Palo Alto, California 94304-1104, USA.
Chomarat
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Djossou
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O
Bidaud
C
C
McKenzie
A N
AN
Miossec
P
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Banchereau
J
J
Zurawski
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G
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001665:Binding Sites; D001667:Binding, Competitive; D002478:Cells, Cultured; D006801:Humans; D018793:Interleukin-13 / Q000037:antagonists & inhibitors / Q000378:metabolism; D053661:Interleukin-13 Receptor alpha1 Subunit; D051379:Mice; D008807:Mice, Inbred BALB C; D018123:Receptors, Interleukin / Q000378:metabolism*; D053660:Receptors, Interleukin-13; D019948:Receptors, Interleukin-4
D000911:Antibodies, Monoclonal; C508181:IL13RA1 protein, human; C508183:Il13ra1 protein, mouse; D018793:Interleukin-13; D053661:Interleukin-13 Receptor alpha1 Subunit; D018123:Receptors, Interleukin; D053660:Receptors, Interleukin-13; D019948:Receptors, Interleukin-4