The Primary Binding Subunit of the Human Interleukin-4 Receptor Is Also a Component of the Interleukin-13 Receptor

• Published in: The Journal of biological chemistry 1995-06, Vol.270 (23), p.13869-13878
• Main Authors: Zurawski, Sandra M., Chomarat, Pascale, Djossou, Odile, Bidaud, Christine, McKenzie, Andrew N.J., Miossec, Pierre, Banchereau, Jacques, Zurawski, Gerard
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Monoclonal - immunology; Binding Sites; Binding, Competitive; Cells, Cultured; Humans; Interleukin-13 - antagonists & inhibitors; Interleukin-13 - metabolism; Interleukin-13 Receptor alpha1 Subunit; Mice; Mice, Inbred BALB C; Receptors, Interleukin - metabolism; Receptors, Interleukin-13; Receptors, Interleukin-4
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.270.23.13869

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-4Rα) 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. Hyperexpression of IL-4Rα 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-4Rα 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-4Rα is a secondary component of IL-13R.