title: The amino-terminal helix of GM-CSF and IL-5 governs high affinity binding to their receptors.
abstract: Transduction of the biological effects of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-5 (IL-5) requires the interaction of each cytokine with at least two cell surface receptor components, one of which is shared between these two cytokines. A strategy is presented that allowed us to identify receptor binding determinants in GM-CSF and IL-5. Mixed species (human and mouse) receptors were used to locate unique receptor binding domains on a series of human-mouse hybrid GM-CSF and IL-5 cytokines. Results show that the interaction of these two cytokines with the shared subunit of their high affinity receptor complexes is governed by a very small part of their peptide chains. The presence of a few key residues in the amino-terminal alpha-helix of each ligand is sufficient to confer specificity to the interaction. Comparison with other cytokines suggests that the amino-terminal helix of many of these proteins may contain the recognition element for the formation of high affinity binding sites with the alpha subunit of their multi-component receptors.
authors.affiliation: Department of Molecular Biology, DNAX Research Institute of Molecular and Cellular Biology, Palo Alto, CA 94304-1104.
authors.forename: A B
authors.initials: AB
authors.lastname: Shanafelt
authors.forename: A
authors.initials: A
authors.lastname: Miyajima
authors.forename: T
authors.initials: T
authors.lastname: Kitamura
authors.forename: R A
authors.initials: RA
authors.lastname: Kastelein
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D004274:DNA, Recombinant / Q000235:genetics; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D015848:Interleukin-5 / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism*; D014161:Transduction, Genetic; D014162:Transfection
chemical_list: D004274:DNA, Recombinant; D015848:Interleukin-5; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; D016178:Granulocyte-Macrophage Colony-Stimulating Factor