Functional cartography of the ectodomain of the type I interferon receptor subunit ifnar1
| Autor: | Gilles Uzé, Imke Peters, Peter Lamken, Jose Van der Heyden, Jacob Piehler, Martynas Gavutis |
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| Rok vydání: | 2005 |
| Předmět: |
Models
Molecular Protein Folding Glycosylation Protein Conformation Green Fluorescent Proteins Lipid Bilayers Molecular Sequence Data Cell Separation Receptor Interferon alpha-beta Biology Ligands Transfection Binding Competitive Cell Line Structural Biology Enzyme-linked receptor Escherichia coli Humans Amino Acid Sequence Binding site Receptor Molecular Biology Receptors Interferon Chromatography Binding Sites Base Sequence Sequence Homology Amino Acid Cell Membrane Interferon-alpha Membrane Proteins Interferon-beta Ligand (biochemistry) Flow Cytometry Molecular biology Protein Structure Tertiary Kinetics Ectodomain Interleukin-21 receptor Electrophoresis Polyacrylamide Gel Signal transduction Cytokine receptor Protein Binding Signal Transduction |
| Zdroj: | Journal of molecular biology. 350(3) |
| ISSN: | 0022-2836 |
| Popis: | Ligand-induced cross-linking of the type I interferon (IFN) receptor subunits ifnar1 and ifnar2 induces a pleiotrophic cellular response. Several studies have suggested differential signal activation by flexible recruitment of the accessory receptor subunit ifnar1. We have characterized the roles of the four Ig-like sub-domains (SDs) of the extracellular domain of ifnar1 (ifnar1-EC) for ligand recognition and receptor assembling. Various sub-fragments of ifnar1-EC were expressed in insect cells and purified to homogeneity. Solid phase binding assays with the ligands IFN(alpha)2 and IFN(beta) revealed that all three N-terminal SDs were required and sufficient for ligand binding, and that IFN(alpha)2 and IFN(beta) compete for this binding site. Cellular binding assays with different fragments, however, highlighted the key role of the membrane-proximal SD for the formation of an in situ IFN-receptor complex. Even substitution with the corresponding SD from homologous cytokine receptors did not restore high-affinity ligand binding. Receptor assembling analysis on supported lipid bilayers in vitro revealed that the membrane-proximal SD controls appropriate orientation of the receptor on the membrane, which is required for efficient association of ifnar1 into the ternary complex. |
| Databáze: | OpenAIRE |
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