Rescue of ligand binding of a mutant IGF-I receptor by complementation.
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.
Chakravarty
Anders
A
Receptor Biology Laboratory, Novo Nordisk A/S, Hagedorn Research Institute, DK-2820 Gentofte, Denmark.
Hinrichsen
Jane
J
Whittaker
Linda
L
Whittaker
Jonathan
J
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*
D008024:Ligands; D017526:Receptor, IGF Type 1