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Publication Abstract from PubMed

Interleukin 27 (IL-27) is a heterodimeric cytokine that elicits potent immunosuppressive responses. Comprised of EBI3 and p28 subunits, IL-27 binds GP130 and IL-27Ralpha receptor chains to activate the JAK/STAT signaling cascade. However, how these receptors recognize IL-27 and form a complex capable of phosphorylating JAK proteins remains unclear. Here, we used cryo electron microscopy (cryoEM) and AlphaFold modeling to solve the structure of the IL-27 receptor recognition complex. Our data show how IL-27 serves as a bridge connecting IL-27Ralpha (domains 1-2) with GP130 (domains 1-3) to initiate signaling. While both receptors contact the p28 component of the heterodimeric cytokine, EBI3 stabilizes the complex by binding a positively charged surface of IL-27Ralpha and Domain 1 of GP130. We find that assembly of the IL-27 receptor recognition complex is distinct from both IL-12 and IL-6 cytokine families and provides a mechanistic blueprint for tuning IL-27 pleiotropic actions.

Structural insights into the assembly and activation of the IL-27 signaling complex.,Jin Y, Fyfe PK, Gardner S, Wilmes S, Bubeck D, Moraga I EMBO Rep. 2022 Oct 6;23(10):e55450. doi: 10.15252/embr.202255450. Epub 2022 Aug , 3. PMID:35920255^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.