title: Slow-dissociation effect of common signaling subunit beta c on IL5 and GM-CSF receptor assembly.
abstract: Receptor activation by IL5 and GM-CSF is a sequential process that depends on their interaction with a cytokine-specific subunit alpha and recruitment of a common signaling subunit beta (betac). In order to elucidate the assembly dynamics of these receptor subunits, we performed kinetic interaction analysis of the cytokine-receptor complex formation by a surface plasmon resonance biosensor. Using the extracellular domains of receptor fused with C-terminal V5-tag, we developed an assay method to co-anchor alpha and betac subunits on the biosensor surface. We demonstrated that dissociation of the cytokine-receptor complexes was slower when both subunits were co-anchored on the biosensor surface than when alpha subunit alone was anchored. The slow-dissociation effect of betac had a similar impact on GM-CSF receptor stabilization to that of IL5. The effects were abolished by alanine replacement of either Tyr18 or Tyr344 residue in betac, which together constitute key parts of a cytokine binding epitope. The data argue that betac plays an important role in preventing the ligand-receptor complexes from rapidly dissociating. This slow-dissociation effect of betac explains how, when multiple betac cytokine receptor alpha subunits are present on the same cell surface, selective betac usage can be controlled by sequestration in stabilized cytokine-alpha-betac complexes.
authors.affiliation: Drexel University College of Medicine, Department of Biochemistry and Molecular Biology, 245 North, 15th Street, Mail Stop 497, New College Building, Room 11102, Philadelphia, PA 19102-1192, USA.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Ishino
authors.affiliation: Drexel University College of Medicine, Department of Biochemistry and Molecular Biology, 245 North, 15th Street, Mail Stop 497, New College Building, Room 11102, Philadelphia, PA 19102-1192, USA.
authors.forename: Adrian E
authors.initials: AE
authors.lastname: Harrington
authors.affiliation: Drexel University College of Medicine, Department of Biochemistry and Molecular Biology, 245 North, 15th Street, Mail Stop 497, New College Building, Room 11102, Philadelphia, PA 19102-1192, USA.
authors.forename: Meirav
authors.initials: M
authors.lastname: Zaks-Zilberman
authors.affiliation: Drexel University College of Medicine, Department of Biochemistry and Molecular Biology, 245 North, 15th Street, Mail Stop 497, New College Building, Room 11102, Philadelphia, PA 19102-1192, USA.
authors.forename: Jeffery J
authors.initials: JJ
authors.lastname: Scibek
authors.affiliation: Drexel University College of Medicine, Department of Biochemistry and Molecular Biology, 245 North, 15th Street, Mail Stop 497, New College Building, Room 11102, Philadelphia, PA 19102-1192, USA. Electronic address: Irwin.Chaiken@DrexelMed.edu.
authors.forename: Irwin
authors.initials: I
authors.lastname: Chaiken
mesh_terms: D000818:Animals; D002460:Cell Line; D053648:Cytokine Receptor Common beta Subunit / Q000378:metabolism / Q000502:physiology*; D004330:Drosophila; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D015848:Interleukin-5 / Q000378:metabolism*; D053666:Interleukin-5 Receptor alpha Subunit / Q000378:metabolism; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor / Q000378:metabolism*; D053649:Receptors, Interleukin-5 / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D053648:Cytokine Receptor Common beta Subunit; C508599:IL5 protein, human; C485918:IL5RA protein, human; D015848:Interleukin-5; D053666:Interleukin-5 Receptor alpha Subunit; D016187:Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; D053649:Receptors, Interleukin-5; D016178:Granulocyte-Macrophage Colony-Stimulating Factor