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Cell. 2011 Aug 19;146(4):621-32. doi: 10.1016/j.cell.2011.06.048.

Structural linkage between ligand discrimination and receptor activation by type I interferons.

Author information

1
Howard Hughes Medical Institute, Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA.

Abstract

Type I Interferons (IFNs) are important cytokines for innate immunity against viruses and cancer. Sixteen human type I IFN variants signal through the same cell-surface receptors, IFNAR1 and IFNAR2, yet they can evoke markedly different physiological effects. The crystal structures of two human type I IFN ternary signaling complexes containing IFNα2 and IFNω reveal recognition modes and heterotrimeric architectures that are unique among the cytokine receptor superfamily but conserved between different type I IFNs. Receptor-ligand cross-reactivity is enabled by conserved receptor-ligand "anchor points" interspersed among ligand-specific interactions that "tune" the relative IFN-binding affinities, in an apparent extracellular "ligand proofreading" mechanism that modulates biological activity. Functional differences between IFNs are linked to their respective receptor recognition chemistries, in concert with a ligand-induced conformational change in IFNAR1, that collectively control signal initiation and complex stability, ultimately regulating differential STAT phosphorylation profiles, receptor internalization rates, and downstream gene expression patterns.

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PMID:
21854986
PMCID:
PMC3166218
DOI:
10.1016/j.cell.2011.06.048
[Indexed for MEDLINE]
Free PMC Article

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