The Role of Interchain Heterodisulfide Formation in Activation of the Human Common beta and Mouse beta(IL-3) Receptors
- Author(s)
- Mirza, S; Chen, JL; Murphy, JM; Young, IG;
- Details
- Publication Year 2010-08-06,Volume 285,Issue #32,Page 24759-24768
- Journal Title
- JOURNAL OF BIOLOGICAL CHEMISTRY
- Publication Type
- Journal Article
- Abstract
- The cytokines, interleukin-3 (IL-3), interleukin-5 (IL-5), and granulocyte-macrophage colony-stimulating factor (GM-CSF), exhibit overlapping activities in the regulation of hematopoietic cells. In humans, the common beta (beta c) receptor is shared by the three cytokines and functions together with cytokine-specific alpha subunits in signaling. A widely accepted hypothesis is that receptor activation requires heterodisulfide formation between the domain 1 D-E loop disulfide in human beta c (h beta c) and unidentified cysteine residues in the N-terminal domains of the alpha receptors. Since the development of this hypothesis, new data have been obtained showing that domain 1 of h beta c is part of the cytokine binding epitope of this receptor and that an IL-3R alpha isoform lacking the N-terminal Ig-like domain (the "SP2" isoform) is competent for signaling. We therefore investigated whether distortion of the domain 1-domain 4 ligand-binding epitope in h beta c and the related mouse receptor, beta(IL-3), could account for the loss of receptor signaling when the domain 1 D-E loop disulfide is disrupted. Indeed, mutation of the disulfide in h beta c led to both a complete loss of high affinity binding with the humanIL-3R alpha SP2 isoform and of downstream signaling. Mutation of the orthologous residues in the mouse IL-3-specific receptor, beta(IL-3), not only precluded direct binding of mouse IL-3 but also resulted in complete loss of high affinity binding and signaling with the mouse IL-3R alpha SP2 isoform. Our data are most consistent with a role for the domain 1 D-E loop disulfide of h beta c and beta(IL-3) in maintaining the precise positions of ligand-binding residues necessary for normal high affinity binding and signaling.
- Publisher
- AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
- Keywords
- COLONY-STIMULATING FACTOR; GM-CSF RECEPTORS; COMPLETE EXTRACELLULAR DOMAIN; HIGH-AFFINITY BINDING; IL-5 RECEPTORS; INTERLEUKIN-5 RECEPTOR; EXPRESSION CLONING; SIGNALING COMPLEX; CRYSTAL-STRUCTURE; LIGAND-BINDING
- Publisher's Version
- https://doi.org/10.1074/jbc.M109.097881
- Terms of Use/Rights Notice
- Refer to copyright notice on published article.
Creation Date: 2010-08-06 12:00:00