| Autor: |
Devos, René, Guisez, Yves, Plaetinck, Geert, Cornelis, Sigrid, Tavernier, Jan, van der Heyden, José, Foley, Louise H., Scheffler, Julie E. |
| Předmět: |
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| Zdroj: |
European Journal of Biochemistry; 10/15/94, Vol. 225 Issue 2, p635-640, 6p |
| Abstrakt: |
Using a fusion protein of the human interleukin-5-receptor α chain (hIL5R α) and the human IgG C γ 3 chain (hIL5R α-h γ 3), we have developed a solid-phase assay for high-flux screening of a collection of synthetic compounds. We report on the identification of isothiazolone derivatives as potent inhibitors of binding of interleukin-5 (IL5) to the hIL5R α, as measured in a solid-phase assay (soluble hIL5R α or hIL5R α-h γ 3) or on COS-1 cells expressing the hIL5R α on the cell membrane. The binding of hIL4 and human granulocyte macrophage colony-stimulating factor (hGM-CSF) to their respective receptors is not inhibited by the isothiazolones in similar assay systems. Scatchard analysis revealed that these compounds caused a decrease in affinity of the IL5R α for IL5. The inhibition of binding IL5 to its receptor by the isothiazolone derivatives is abrogated by free-sulfhydryl-containing compounds such as dithiothreitol, indicating that the isothiazolones react with the sulfhydryl group of free cysteine residues in the hIL5R α. Mutation of Cys66 led to a receptor which still binds hIL5, but which was insensitive to the inhibition by isothiazolones. Mutation of Cys249 and Cys296 to serine resulted in complete loss of IL-5-binding activity. The use of radio-labeled isothiazolone confirmed that Cys66, present in the first domain of the receptor, is the target for covalent modification leading to a decrease in affinity. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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