de Weerd Nicole A, Matthews Antony Y, Pattie Phillip R, Bourke Nollaig M, Lim San S, Vivian Julian P, Rossjohn Jamie, Hertzog Paul J
From the Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, 27-31 Wright Street, Clayton, Victoria 3168, Australia,
Department of Molecular and Translational Sciences, School of Clinical Sciences at Monash Health, Monash University, 27-31 Wright Street, Clayton, Victoria 3168, Australia.
J Biol Chem. 2017 May 5;292(18):7554-7565. doi: 10.1074/jbc.M116.773788. Epub 2017 Mar 13.
The interaction of IFN-β with its receptor IFNAR1 (interferon α/β receptor subunit 1) is vital for host-protective anti-viral and anti-proliferative responses, but signaling via this interaction can be detrimental if dysregulated. Whereas it is established that IFNAR1 is an essential component of the IFNAR signaling complex, the key residues underpinning the IFN-β-IFNAR1 interaction are unknown. Guided by the crystal structure of the IFN-β-IFNAR1 complex, we used truncation variants and site-directed mutagenesis to investigate domains and residues enabling complexation of IFN-β to IFNAR1. We have identified an interface on IFNAR1-subdomain-3 that is differentially utilized by IFN-β and IFN-α for signal transduction. We used surface plasmon resonance and cell-based assays to investigate this important IFN-β binding interface that is centered on IFNAR1 residues Tyr and Tyr binding the C and N termini of the B and C helices of IFN-β, respectively. Using IFNAR1 and IFN-β variants, we show that this interface contributes significantly to the affinity of IFN-β for IFNAR1, its ability to activate STAT1, the expression of interferon stimulated genes, and ultimately to the anti-viral and anti-proliferative properties of IFN-β. These results identify a key interface created by IFNAR1 residues Tyr and Tyr interacting with IFN-β residues Phe, Leu, Glu, Thr, Val, and Arg that underlie IFN-β-IFNAR1-mediated signaling and biological processes.
干扰素-β（IFN-β）与其受体IFNAR1（干扰素α/β受体亚基1）的相互作用对于宿主保护性抗病毒和抗增殖反应至关重要，但如果这种相互作用失调，通过其进行的信号传导可能会产生有害影响。虽然已经确定IFNAR1是IFNAR信号复合物的重要组成部分，但支撑IFN-β与IFNAR1相互作用的关键残基尚不清楚。在IFN-β-IFNAR1复合物晶体结构的指导下，我们使用截短变体和定点诱变来研究使IFN-β与IFNAR1形成复合物的结构域和残基。我们在IFNAR1亚结构域3上确定了一个界面，IFN-β和IFN-α对其利用方式不同，用于信号转导。我们使用表面等离子体共振和基于细胞的分析方法来研究这个重要的IFN-β结合界面，该界面以IFNAR1残基Tyr和Tyr为中心，分别结合IFN-β的B和C螺旋的C端和N端。使用IFNAR1和IFN-β变体，我们表明该界面显著有助于IFN-β对IFNAR1的亲和力、其激活STAT1的能力、干扰素刺激基因的表达，并最终有助于IFN-β的抗病毒和抗增殖特性。这些结果确定了一个由IFNAR1残基Tyr和Tyr与IFN-β残基Phe、Leu、Glu、Thr、Val和Arg相互作用形成的关键界面，该界面是IFN-β-IFNAR1介导的信号传导和生物学过程的基础。
