title: Cyclic GMP-AMP synthase is activated by double-stranded DNA-induced oligomerization.
abstract: Cyclic GMP-AMP synthase (cGAS) is a cytosolic DNA sensor mediating innate antimicrobial immunity. It catalyzes the synthesis of a noncanonical cyclic dinucleotide, 2',5' cGAMP, that binds to STING and mediates the activation of TBK1 and IRF-3. Activated IRF-3 translocates to the nucleus and initiates the transcription of the IFN-β gene. The structure of mouse cGAS bound to an 18 bp dsDNA revealed that cGAS interacts with dsDNA through two binding sites, forming a 2:2 complex. Enzyme assays and IFN-β reporter assays of cGAS mutants demonstrated that interactions at both DNA binding sites are essential for cGAS activation. Mutagenesis and DNA binding studies showed that the two sites bind dsDNA cooperatively and that site B plays a critical role in DNA binding. The structure of mouse cGAS bound to dsDNA and 2',5' cGAMP provided insight into the catalytic mechanism of cGAS. These results demonstrated that cGAS is activated by dsDNA-induced oligomerization.
authors: Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128, USA.
authors: Xin
authors: X
authors: Li
authors: Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128, USA.
authors: Chang
authors: C
authors: Shu
authors: Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA.
authors: Guanghui
authors: G
authors: Yi
authors: Department of Molecular Genetics, Biochemistry & Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA.
authors: Catherine T
authors: CT
authors: Chaton
authors: Department of Molecular Genetics, Biochemistry & Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA.
authors: Catherine L
authors: CL
authors: Shelton
authors: Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128, USA.
authors: Jiasheng
authors: J
authors: Diao
authors: X-Ray Science Division, Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA.
authors: Xiaobing
authors: X
authors: Zuo
authors: Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, IN 47405, USA.
authors: C Cheng
authors: CC
authors: Kao
authors: Department of Molecular Genetics, Biochemistry & Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA.
authors: Andrew B
authors: AB
authors: Herr
authors: Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843-2128, USA. Electronic address: pingwei@tamu.edu.
authors: Pingwei
authors: P
authors: Li
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000235:genetics; D020134:Catalytic Domain; D004247:DNA / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D009712:Nucleotides, Cyclic / Q000378:metabolism; D009713:Nucleotidyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D000099235:Cyclic Guanosine Monophosphate-Adenosine Monophosphate Synthase
chemical_list: D004247:DNA; D009712:Nucleotides, Cyclic; D009713:Nucleotidyltransferases; C584311:cyclic guanosine monophosphate-adenosine monophosphate; C578391:cGAS protein, mouse; D000099235:Cyclic Guanosine Monophosphate-Adenosine Monophosphate Synthase