title: Conformational changes mediate interleukin-10 receptor 2 (IL-10R2) binding to IL-10 and assembly of the signaling complex.
abstract: Interleukin-10 receptor 2 (IL-10R2) is a critical component of the IL-10.IL-10R1.IL-10R2 complex which regulates IL-10-mediated immunomodulatory responses. The ternary IL-10 signaling complex is assembled in a sequential order with the IL-10.IL-10R1 interaction occurring first followed by engagement of the IL-10R2 chain. In this study we map the IL-10R2 binding site on IL-10 using surface plasmon resonance and cell-based assays. Critical IL-10R2 binding residues are located in helix A adjacent to the previously identified IL-10R1 recognition surface. Interestingly, IL-10R2 binding residues located in the N-terminal end of helix A exhibit large structural differences between unbound cIL-10 and cIL-10.IL-10R1 crystal structures. This suggests IL-10R1-induced conformational changes regulate IL-10R2 binding and assembly of the ternary IL-10.IL-10R1.IL-10R2 complex. The basic mechanistic features of the assembly process are likely shared by six additional class-2 cytokines (viral IL-10s, IL-22, IL-26, IL-28A, IL28B, and IL-29) to promote IL-10R2 binding to six additional receptor complexes. These studies highlight the importance of structure in regulating low affinity protein-protein interactions and IL-10 signal transduction.
authors.affiliation: Department of Microbiology and Center for Biophysical Sciences and Engineering, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
authors.forename: Sung Il
authors.initials: SI
authors.lastname: Yoon
authors.forename: Naomi J
authors.initials: NJ
authors.lastname: Logsdon
authors.forename: Faruk
authors.initials: F
authors.lastname: Sheikh
authors.forename: Raymond P
authors.initials: RP
authors.lastname: Donnelly
authors.forename: Mark R
authors.initials: MR
authors.lastname: Walter
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D004926:Escherichia coli; D016753:Interleukin-10 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D053710:Interleukin-10 Receptor beta Subunit / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D011487:Protein Conformation; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D053710:Interleukin-10 Receptor beta Subunit; D016753:Interleukin-10