Nucleic acids from bacteria or viruses induce potent immune responses in infected cells <sup>1-4 </sup>. The detection of pathogen-derived nucleic acids is a central strategy by which the host senses infection and initiates protective immune response ...
Nucleic acids from bacteria or viruses induce potent immune responses in infected cells 1-4 . The detection of pathogen-derived nucleic acids is a central strategy by which the host senses infection and initiates protective immune responses 5,6 . Cyclic GMP-AMP synthase (cGAS) is a double-stranded DNA sensor 7,8 . It catalyses the synthesis of cyclic GMP-AMP (cGAMP) 9-12 , which stimulates the induction of type I interferons through the STING-TBK1-IRF-3 signalling axis 13-15 . STING oligomerizes after binding of cGAMP, leading to the recruitment and activation of the TBK1 kinase 8,16 . The IRF-3 transcription factor is then recruited to the signalling complex and activated by TBK1 8,17-20 . Phosphorylated IRF-3 translocates to the nucleus and initiates the expression of type I interferons 21 . However, the precise mechanisms that govern activation of STING by cGAMP and subsequent activation of TBK1 by STING remain unclear. Here we show that a conserved PLPLRT/SD motif within the C-terminal tail of STING mediates the recruitment and activation of TBK1. Crystal structures of TBK1 bound to STING reveal that the PLPLRT/SD motif binds to the dimer interface of TBK1. Cell-based studies confirm that the direct interaction between TBK1 and STING is essential for induction of IFNβ after cGAMP stimulation. Moreover, we show that full-length STING oligomerizes after it binds cGAMP, and highlight this as an essential step in the activation of STING-mediated signalling. These findings provide a structural basis for the development of STING agonists and antagonists for the treatment of cancer and autoimmune disorders.
Organizational Affiliation:
Department of Biological Science, Florida State University, Tallahassee, FL, USA.,Department of Chemistry, Texas A&M University, College Station, TX, USA.,Department of Microbial Pathogenesis and Immunology, Texas A&M University Health Science Center, College Station, TX, USA.,Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M University Health Science Center, College Station, TX, USA.,Molecular Biophysics and Integrated Bioimaging, Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.,Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA.,Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA. pingwei@tamu.edu.
N-(3-{[5-iodo-4-({3-[(thiophen-2-ylcarbonyl)amino]propyl}amino)pyrimidin-2-yl]amino}phenyl)pyrrolidine-1-carboxamide C23 H26 I N7 O2 S VAVXGGRQQJZYBL-UHFFFAOYSA-N
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