Kinetics of cytokine receptor trafficking determine signaling and functional selectivity

Elife. 2019 Nov 27:8:e49314. doi: 10.7554/eLife.49314.

Abstract

Cytokines activate signaling via assembly of cell surface receptors, but it is unclear whether modulation of cytokine-receptor binding parameters can modify biological outcomes. We have engineered IL-6 variants with different affinities to gp130 to investigate how cytokine receptor binding dwell-times influence functional selectivity. Engineered IL-6 variants showed a range of signaling amplitudes and induced biased signaling, with changes in receptor binding dwell-times affecting more profoundly STAT1 than STAT3 phosphorylation. We show that this differential signaling arises from defective translocation of ligand-gp130 complexes to the endosomal compartment and competitive STAT1/STAT3 binding to phospho-tyrosines in gp130, and results in unique patterns of STAT3 binding to chromatin. This leads to a graded gene expression response and differences in ex vivo differentiation of Th17, Th1 and Treg cells. These results provide a molecular understanding of signaling biased by cytokine receptors, and demonstrate that manipulation of signaling thresholds is a useful strategy to decouple cytokine functional pleiotropy.

Keywords: bias signaling; cytokine engineering; cytokine signaling; endosomal traffic; functional pleiotropy; human; immunology; inflammation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Cell Differentiation
  • Cloning, Molecular
  • Cytokine Receptor gp130 / chemistry*
  • Cytokine Receptor gp130 / genetics
  • Cytokine Receptor gp130 / metabolism
  • Endosomes / chemistry
  • Endosomes / metabolism
  • Gene Expression
  • HeLa Cells
  • Humans
  • Interleukin-6 / chemistry*
  • Interleukin-6 / genetics
  • Interleukin-6 / metabolism
  • Kinetics
  • Models, Molecular
  • Phosphorylation
  • Primary Cell Culture
  • Protein Binding
  • Protein Conformation, alpha-Helical
  • Protein Conformation, beta-Strand
  • Protein Engineering / methods
  • Protein Interaction Domains and Motifs
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • STAT1 Transcription Factor / genetics
  • STAT1 Transcription Factor / metabolism*
  • STAT3 Transcription Factor / genetics
  • STAT3 Transcription Factor / metabolism
  • Signal Transduction
  • T-Lymphocytes, Regulatory / cytology
  • T-Lymphocytes, Regulatory / immunology
  • T-Lymphocytes, Regulatory / metabolism*
  • Th1 Cells / cytology
  • Th1 Cells / immunology
  • Th1 Cells / metabolism*
  • Th17 Cells / cytology
  • Th17 Cells / immunology
  • Th17 Cells / metabolism*

Substances

  • IL6 protein, human
  • Interleukin-6
  • Recombinant Proteins
  • STAT1 Transcription Factor
  • STAT1 protein, human
  • STAT3 Transcription Factor
  • STAT3 protein, human
  • Cytokine Receptor gp130

Associated data

  • GEO/GSE130810