title: Rescue of ligand binding of a mutant IGF-I receptor by complementation.
abstract: The IGF-I receptor binds IGF-I with complex kinetics characterized by a curvilinear Scatchard plot, suggesting receptor heterogeneity and apparent negative cooperativity. To explore the molecular mechanisms underlying these properties, we have characterized the binding of a hybrid receptor formed from a wild-type receptor monomer and a mutant receptor monomer devoid of binding activity. Receptor hybrids were generated by transient co-transfection of cDNAs encoding wild-type and mutant receptors with unique epitope tags. Hybrid receptors were purified from transfected cells by sequential immuno-affinity chromatography and their ligand-binding properties were determined. Complementation produced a hybrid with near wild-type affinity. Dissociation studies demonstrated that the hybrid did not exhibit negative cooperativity.
authors.affiliation: Receptor Biology Laboratory, Novo Nordisk A/S, Hagedorn Research Institute, DK-2820 Gentofte, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Chakravarty
authors.forename: Jane
authors.initials: J
authors.lastname: Hinrichsen
authors.forename: Linda
authors.initials: L
authors.lastname: Whittaker
authors.forename: Jonathan
authors.initials: J
authors.lastname: Whittaker
mesh_terms: D000818:Animals; D002460:Cell Line; D019281:Dimerization; D007700:Kinetics; D008024:Ligands; D009154:Mutation; D011485:Protein Binding; D017526:Receptor, IGF Type 1 / Q000235:genetics* / Q000378:metabolism*
chemical_list: D008024:Ligands; D017526:Receptor, IGF Type 1